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  • 1.
    Beltran, Francisco
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Sommerfeldt, Nelson
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Padovani, Filippo
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Rolando, Davide
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Solar Heat Pumps and Self-Consumption Can (and should) electricity suppliers encourage thermal storage?2022Ingår i: 2022 BuildSim Nordic, BSN 2022, EDP Sciences , 2022, artikel-id 06005Konferensbidrag (Refereegranskat)
    Abstract [en]

    Heat pumps and water tanks can be used to increase PV self-consumption in buildings without any additional equipment, but there is sometimes a lack of economic incentives to maximize it that limits economic gains. Therefore, pricing conditions need to change in order to make self-consumption strategies more interesting for prosumers. This study aims at determining what, if any, unsubsidized market conditions could lead to economically motivated self-consumption control strategies with solar heat pumps. A sensitivity analysis is used on multiple pricing models based on current market conditions for a solar PV and ground source heat pump system for a single-family house in Norrköping, Sweden. The results show that control strategies aimed at maximizing self-consumption have very little impact on net costs, regardless of pricing model or variation in price. Feed-in-bonus is the most important aspect when comparing different pricing schemes, and no other sensitivity comes close.

  • 2.
    Fischer, Andreas C.
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Toral, T. R.
    Lindberg, K. B.
    Wille-Haussmann, B.
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Investigation of Thermal Storage Operation Strategies with Heat Pumps in German Multi Family Houses2014Ingår i: Energy Procedia, Elsevier, 2014, s. 137-144Konferensbidrag (Refereegranskat)
    Abstract [en]

    The use of air source heat pumps is an efficient method to provide heat for space heating and domestic hot water in residential buildings, which cover roughly one third of the German domestic energy use. Capacity controlled heat pumps are gaining increased market share and provide high flexibility in operation. The possibility to use thermal storage to decouple thermal production and electric load from the heat pump can be used for operation strategies, hereby increasing the possibility to integrate electricity production from renewable energy sources. In the work presented, a range of operational strategies for capacity controlled heat pumps connected to a thermal storage in German multifamily houses are introduced and evaluated. The use cases include maximization of energy performance, cost minimization and utilization of on-site photovoltaic production. For optimal storage operation a model predictive control (MPC) approach using quadratic programming is presented together with simplified models of the multi-family house, a thermal storage and a capacity controlled air-to-water heat pump, the MPC creates a control signal to the heat pump. The resulting control signal is then applied to a detailed heat pump model to investigate the impact on the efficiency of the heat pump unit and thereby its electric energy consumption with different storage options.Results show that the MPC strategy is able to adapt to different objectives. One of the most important findings is that changing the objective towards a variable day-ahead-price-based operation leads to decreased heat pump efficiency but increases revenue. The sensitivity analysis towards storage size shows little influence in the range of sizes investigated.

  • 3. Fischer, D.
    et al.
    Rautenberg, F.
    Wirtz, T.
    Wille-Haussmann, B.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Smart meter enabled control for variable speed heat pumps to increase PV self-consumption2015Ingår i: Refrigeration Science and Technology, International Institute of Refrigeration , 2015, s. 4049-4056Konferensbidrag (Refereegranskat)
    Abstract [en]

    In the last five years the costs of photovoltaic systems have decreased considerably making it economically attractive to generate electricity locally. In many countries, self-consumption is the most attractive option to make use of the generated electricity. Variable speed heat pumps - if controlled properly - can take a share of the PV electricity to decrease costs and CO2 emissions for heat generation and increase PV self-consumption. This paper discusses a control strategy that uses real-time smart meter readings and adjusts the compressor speed to adapt heat pump electricity consumption depending on the available PV power. The approach is tested in a detailed building simulation. Self-consumption can be increased by 6% compared to a heat driven control. For the chosen PV size of 10kWp in a German multi-family house, an increase of storage size shows only little possibility for a further increase in self-consumption.

  • 4.
    Fischer, David
    et al.
    Fraunhofer Institute for Solar Energy Systems, Germany.
    Bernhardt, J.
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Wittwer, C.
    Comparison of control approaches for variable speed air source heat pumps considering time variable electricity prices and PV2017Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 204, s. 93-105Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The influence of different control strategies and boundary conditions on heat pump system performance are investigated in this study and the trade-off between complexity and performance of different controllers is addressed. For this purpose five different control approaches for a variable speed air source heat pump in a multi family house are compared for three different use-cases. The used controls differ in complexity and the use of external input data like price and weather forecasts. The use-cases are: Constant electricity prices, time variable electricity prices and PV self-consumption. Four different rule-based controllers are compared to a convex MPC approach, presented in this work. Results show that the MPC approach reduces annual operating cost by 6–11% for constant electricity prices and 6–16% in the case of variable electricity prices. Rule-based approaches lead to cost reductions of 2–4%. MPC could increases PV self-consumption from 56% to 58% up to 64–71%. The rule base approaches are found computationally less demanding and easier to design. However fine-tuning has been considerable work and with changing boundary conditions rules had to be readjusted. It showed that increasing thermal storage without MPC is not beneficial and optimised controls are a prerequisite to benefit from increased storage sizes.

  • 5. Fischer, David
    et al.
    Lindberg, Karen Byskov
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Wittwer, Christof
    Impact of PV and variable prices on optimal system sizing for heat pumps and thermal storage2016Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 128, s. 723-733Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Heat pump (HP) units coupled to thermal storage offer flexibility in operation and hence the possibility to shift electric load. This can be used to increase PV self-consumption or optimise operation under variable electricity prices. A key question is if new sizing procedures for heat pumps, electric boilers and thermal storages are needed when heat pumps operate in a more dynamic environment, or if sizing is still determined by the thermal demand and thus sizing procedures are already well known. This is answered using structural optimisation based on mixed integer linear programming. The optimal system size of a HP, an electric back-up heater and thermal storage are calculated for 37 scenarios to investigate the impact of on-site PV, variable electricity price, space heat demand and domestic hot water demand. The results are compared to today's established sizing procedures for Germany. Results show that the thermal load profile has the strongest influence on system sizing. In most of the scenarios investigated, the established sizing procedures are sufficient. Only large PV sizes, or highly fluctuating electricity prices, create a need for lager storage. However, allowing the storage to be overheated by 10 K, the need for a larger storage only occurs in the extreme scenarios. 

  • 6.
    Fischer, David
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik. Fraunhofer Institute for Solar Energy Systems, Germany.
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    On heat pumps in smart grids: A review2017Ingår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 70, s. 342-357Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    This paper investigates heat pump systems in smart grids, focussing on fields of application and control approaches that have emerged in academic literature. Based on a review of published literature technical aspects of heat pump flexibility, fields of application and control approaches are structured and discussed. Three main categories of applications using heat pumps in a smart grid context have been identified: First stable and economic operation of power grids, second the integration of renewable energy sources and third operation under variable electricity prices. In all fields heat pumps - when controlled in an appropriate manner - can help easing the transition to a decentralized energy system accompanied by a higher share of prosumers and renewable energy sources. Predictive controls are successfully used in the majority of studies, often assuming idealized conditions. Topics for future research have been identified including: a transfer of control approaches from simulation to the field, a detailed techno-economic analysis of heat pump systems under smart grid operation, and the design of heat pump systems in order to increase flexibility are among the future research topics suggested.

  • 7. Fischer, David
    et al.
    Wirtz, T.
    Zerbe, K. D.
    Wille-Haussmann, B.
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Test cases for hardware in the loop testing of air to water heat pump systems in a smart grid context2015Ingår i: Refrigeration Science and Technology, International Institute of Refrigeration, 2015, s. 3666-3673Konferensbidrag (Refereegranskat)
    Abstract [en]

    Heat Pumps for heating and cooling purposes could play an important role in the future energy system. Combined with a thermal storage they offer the possibility for demand side management applications in a smart grid. Optimized utilization of local solar resources can be achieved by increasingly sophisticated control strategies. Smart gird integration and the use of solar resources will bring new challenges to heat pump system design and operation. However standardized testing procedures to compare HP-systems and controllers in a dynamic and possibly smart grid environment are currently lacking. In this work a method to extract representative test days from energy data, to be used in a Hardware In The Loop test is presented. The resulting sequence of 12 test days is compared to the one year data set and tested in building simulation. Yearly heat generation and SPF can be reproduced with an accuracy of above 94% using the test days.

  • 8.
    Fischer, David
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Wolf, T.
    Wapler, J.
    Hollinger, R.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Model-based flexibility assessment of a residential heat pump pool2017Ingår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 118, s. 853-864Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents and demonstrates a methodology to explore the flexibility of a heat pump pool. Three points are in the focus of this work: First the procedure to model a pool of residential heat pump systems. Second the study of the response of a large number of heat pumps when the Smart-Grid-Ready interface is used for direct load control. Third a general assessment of flexibility of a pool of heat pump systems. The presented pool model accounts for the diversity in space heating and domestic hot water demands, the types of heat source and heat distribution systems used and system sizing procedures. The model is validated using field test data. Flexibility is identified by sending trigger signals to a pool of 284 SG-Ready heat pumps and evaluating the response. Flexibility is characterized by maximum power, shiftable energy and regeneration time. Results show that flexibility is highly dependent on the ambient temperature and the use of an electric back-up heater. It is found that using SG-Ready-like signals offers significantly higher flexibility than just switching off heat pumps, as it is mostly done today.

  • 9.
    Francisco, Beltrán
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Sommerfeldt, Nelson
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Jaakko, Eskola
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Empirical investigation of solar photovoltaic-thermal collectors for heat pump integration2024Ingår i: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 248, artikel-id 123175Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study empirically investigates the optimal design features of photovoltaic-thermal (PVT) collectors for integration with ground source heat pump (GSHP) systems, considering technical and economic factors. Outdoor experiments are conducted in Stockholm, Sweden, comparing five unglazed and uninsulated PVT collector designs a) Reference Sheet & Tube b) Sheet & Tube with a narrow air gap between PV and absorber plate c) Box-channel polypropylene d) Finned tube and e) Box-channel aluminum with fins at operating temperatures below ambient. The findings indicate that the box-channel aluminum design with fins, characterized by a superior combination of high zero-loss efficiency and a high U-value, emerges as the ideal PVT design for integration with ground source heat pumps, taking into account both technical and economic considerations. Despite having a relative specific thermal cost 9% higher than the reference collector, this design demonstrates the capability to generate 2,096 kWh/(m2a) of thermal energy, marking an 83.3% increase compared to the reference, with a 136% higher energy-to-mass ratio.

  • 10.
    Hesaraki, Arefeh
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Energy Performance of Ground-source Heat Pump and Photovoltaic/thermal (PV/T) in Retrofitted and New Buildings: Two Case Studies Using Simulation and On-site Measurements2020Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper aims to contribute by presenting calculated and measured electricity usage in two single-family case studies during the heating season of 2019-2020 located in Stockholm, Sweden. The electricity usage included consumption by heat pumps’ compressor to cover space heating and domestic hot water, auxiliary energy for fans and pumps, and ventilation system. The first case study was built in 1936 with an oil burner, which was renovated to a ground-source heat pump (GSHP) in 2015, and the second case study was a new building built in 2013 with a GSHP. The application of photovoltaic/thermal (PVT) systems in combination with GSHP was theoretically investigated for both case studies. Buildings were modelled using the energy simulation tool IDA Indoor Climate and Energy (ICE), and the model was validated against the measured electrical energy usage. PVT was designed to balance the maximum heat production with domestic hot water consumption during the summer months. Simulation results revealed that combining GSHP with 5 m2 grid-connected PVT gave 21% and 22% energy savings in case study 1 and case study 2, respectively. Employing a battery storage to store extra electricity production by PVT increased the energy savings to 24 % and 32 % for case study 1 and case study 2, respectively. Moreover, in both cases approximately half of the total annual domestic hot water need was prepared by 5 m2 PVT.

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  • 11.
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Capacity-controlled Ground Source Heat Pump Systems for Swedish single-family dwellings2012Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The overall objective of this thesis is to develop a structured method to approach the challenge of better understanding the techniques and potential for capacity control in Ground Source Heat Pump (GSHP) systems used in Swedish single-family dwellings. This thesis aims at development of a generic model of the system that can be used for comparative, descriptive, and predictive analysis of capacity controlled GSHP systems in single-family dwellings.

    In order to develop the generic model, first, a conceptual model of the reality of interest is developed based on the objective of the model. Second, a quantitative model of the system is developed based on the conceptual model. Third, experimental studies are carried out in order to obtain better understanding of the behavior of the system and its components and also to validate the capabilities of the model. Furthermore, some examples are presented to show how the generic model developed and evaluated at the previous stages can be used to address the questions in the context of capacity control in GSHP systems.

    As the first example of applications of the generic model, a comparative analysis is made between the annual performance of on/off-controlled and variable-capacity GSHP systems. The results show that dimensioning of the on/off-controlled GSHP unit based on the peak heat demand of the building plays a significant role when the annual performance of the on/off controlled GSHP system is compared with that of the variable speed GSHP system. As the second example, another comparative analysis is performed, this time to compare three common methods whose purpose is to control on/off-controlled GSHP system. Based on the results from the detailed analysis of these three control methods, it is recommended not to use the constant hysteresis method to avoid large supply temperature oscillation or large deviation from the required temperatures.

    Finding a proper brine mass flow rate, either variable or constant, is a challenge when a variable capacity heat pump system (a heat pump system equipped with a variable speed compressor) is designed. Therefore, as the third example of applications of the generic model, analysis is performed on a variable-capacity GSHP system equipped with a variable speed compressor and variable speed pump in U-pipe borehole heat exchanger. The results show that a single speed liquid pump but with a very carefully-selected brine mass flow rate would be still an appropriate option for variable speed heat pump systems, if COP maximization is the main concern.

    Finally, as the fourth example, the performance of a run-around coil heat recovery system equipped with a variable capacity heat pump unit is evaluated over a year. The results show that by retrofitting a well-sized variable capacity heat pump unit to the system, there is a potential to increase the amount of heat provided by the recovery system by more than 70%.

    In addition to the examples shown, the systematic approach and the generic model used in the present study can be applied to improve other control techniques and strategies and find new opportunities which can lead to saving energy and money, reducing the greenhouse gas emissions, and gaining higher credibility for GSHPs in the market.

  • 12.
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Smart fault detection and diagnosis for heat pump systems2015Ingår i: Refrigeration Science and Technology, International Institute of Refrigeration, 2015, s. 3703-3710Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper introduces a holistic approach to develop a Smart Fault Detection and Diagnosis (SFDD) system which can be integrated and widely used in both old and new heat pump systems worldwide. A SFDD acts as the heart of smart heat pump system. It is able to minimize the installation and control errors, couple or decouple the renewable energy sources, make load-shifting possible, detect the performance degradation during operation, avoid unnecessary visual inspections and components replacement, and reduce the maintenance cost and down-time of the system. In order to determine the most important faults in the heat pump system, a comprehensive study is done on the faults reported to both OEMs and a main insurance company in Sweden and the results are briefly presented. The paper also discusses how a knowledge-based Smart Fault Detection and Diagnosis unit should be designed to support the heat pump systems at commissioning, operation, and maintenance phases.

  • 13.
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    The common and costly faults in heat pump systems2014Ingår i: Energy Procedia, 2014, s. 1803-1806Konferensbidrag (Refereegranskat)
    Abstract [en]

    The heat pump market has become mature in many countries. There are millions of heat pumps installed worldwide. So any improvement in the installation, operation, and maintenance of heat pump system can save a considerable amount of energy and cost, and reduce Green House Emissions to a large extent. In order to minimize the number of faults in installation and operation phases and improve the maintenance process, it is essential to obtain knowledge about the common and expensive faults which usually occur in the heat pump systems. Insurance companies and heat pump manufacturers (OEMs) are the best sources to find out the most common and costliest faults recently occurred in the heat pump systems. The present paper describes the results from a comprehensive study done on the most recent faults which were reported to both OEMs and insurance companies in Sweden. According to the results, it is essential to pay a special attention to the control and electronics in heat pump system in order to reduce the number and cost of the faults in the heat pump systems. Furthermore, the results show the importance of system thinking in any effort to minimize, detect or diagnose the faults in heat pump system.

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  • 14.
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Variable capacity heat pump system in a single family house: dynamic modeling and simulation2009Ingår i: Journal of federation of European HVAC association (REHVA), nr 13Artikel i tidskrift (Övrigt vetenskapligt)
  • 15.
    Madani, Hatef
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Acuña, José
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Claesson, Joachim
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Lundqvist, Per
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    The Ground Source Heat Pump: A System Analysis With a Particular Focus on The U-Pipe Borehole Heat Exchanger2010Ingår i: 2010 14th International Heat Transfer Conference, Volume 4, 2010, s. 395-402Konferensbidrag (Refereegranskat)
    Abstract [en]

    The mass flow rate of the secondary refrigerant flowing in the borehole heat exchanger of a ground source heat pump is an influential system parameter whose variation can influence the pumping power, efficiency of the pump, heat distribution in the borehole, heat pump heat capacity, and above all, the system Overall Coefficient Of Performance (COP). The present paper uses both in-situ field measurements and modeling to evaluate these effects. From the field measurements, it can be concluded that the thermal contact between U-pipe channels increases as the brine mass flow rate decreases. Furthermore, the modeling results show that there is a certain optimum brine mass flow rate which gives a maximum overall system COP. Different optimum mass flow rates are obtained for different compressor speed and it is shown that their relation is almost linear. However, concerning system COP maximization, it can be concluded that a constant but carefully-selected brine mass flow rate can still be an appropriate option for the variable capacity heat pump unit studied in the present paper where the compressor frequency changes between 30Hz and 75Hz. Concerning the heat capacity maximization in the system, a variable speed brine pump can be used to help the insufficiently-sized compressor to cover the peak heat demand of the building.

  • 16.
    Madani, Hatef
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Ahmadi, Navid
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Claesson, Joachim
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Lundqvist, Per
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Experimental Analysis of a Variable Capacity Heat Pump System Focusing on the Compressor and Inverter Loss Behavior2010Ingår i: Proceeding International Refrigeration and Air Conditioning Conference, Academic Conferences Publishing, 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    Capacity control with variable speed compressors in heat pump systems is one of the techniques having a potentialfor efficiency improvement in heat pump systems. It is anticipated that the compressor and inverter efficiency areinfluenced by changes of the compressor speed. The present experimental study evaluates these losses in a variablespeed heat pump system.The experimental results show that increasing the compressor speed reduces the heat pump COP up to 30%. Theinverter loss increases as the compressor speed is increased, although the inverter loss as the percentage of the totalcompressor power decreases. Increasing the compressor speed increases the pressure ratio from 2.7 to 5.8,increasing the loss due to the pressure ratio mismatch drastically. Finally, the highest total isentropic efficiency ofthe compressor is obtained when the compressor frequency is close to 50Hz.

  • 17.
    Madani, Hatef
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Claesson, Joachim
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Lundquist, Per
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Capacity control in ground source heat pump systems part II: Comparative analysis between on/off controlled and variable capacity systems2011Ingår i: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 34, nr 8, s. 1934-1942Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present paper, as the second part of two, modeling and simulation was carried out for a Ground Source Heat Pump (GSHP) system in the presence of all the most important interacting sub-systems such as building, ground heat source, electrical auxiliary heater, and the heat pump unit in order to make a fair and comprehensive comparison between the annual performance of on/off controlled and variable capacity systems. The annual modeling showed that dimensioning of the on/off controlled GSHP based on the peak heat demand of the building plays a significant role when the two control strategies are compared: if the on/off controlled GSHP is dimensioned to cover only 55% of the peak heat demand of the building, the electrical auxiliary, which then covers about 10% of the annual heating demand of the building, makes the SPF of the on/off controlled GSHP to be lower than the one of the variable speed system. On the contrary, when the on/off controlled system is dimensioned to cover more than 65% of the building's peak heat demand, i.e. more than 95% of the annual heat demand of the building, there is no considerable difference between the SPFs of the on/off controlled and variable capacity systems.

  • 18.
    Madani, Hatef
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Claesson, Joachim
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    lundqvist, Per
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    A descriptive and comparative analysis of three common control techniques for an on/off controlled Ground Source Heat Pump (GSHP) system2013Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 65, s. 1-9Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present paper, three common methods in order to control an on/off controlled Ground Source Heat Pump (GSHP) system called "Constant hysteresis", "Floating hysteresis", and "Degree-Minute" methods are comprehensively described. Then, the generic model already developed by the authors is used in order to do the dynamic simulation of the systems with three different control methods over a year and making the comparison between them. The results from annual modeling of the systems show that the mean temperature of the heating water supplied to the building for the system controlled with degree-minute method is always close to the required temperature, regardless of the climatic boundary conditions over a typical year, whereas, the average supply temperature for the system with constant hysteresis method is mostly higher or lower than the required temperature, depending on the boundary condition. Regarding the annual energy use, the degree-minute and constant hysteresis methods have the lowest and highest annual energy use respectively. Switching from constant hysteresis to floating hysteresis method, the annual energy use will become lower and the mean temperature of the heating water supplied to the building will be closer to the required one.

  • 19.
    Madani, Hatef
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Claesson, Joachim
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    lundqvist, Per
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Retrofitting a variable capacity heat pump to a ventilation heat recovery system: modeling and performance analysis2010Konferensbidrag (Övrigt vetenskapligt)
  • 20.
    Madani, Hatef
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Claesson, Joachim
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Lundqvist, Per
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Variable capacity heat pump systems, modeling and simulation2008Ingår i: 9th International Energy Agency Heat pump conference, 2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    Variable speed compressor is one of the most promising ways to modulate thecapacity of heat pump units. The paper describes some common obstacles in the evaluationof variable speed heat pump systems. The inconsistencies between the compared systemcomponents, the complexity in the measurement of some detailed parameters, too muchfocus on unit efficiency solely, but also not considering the effect of system dynamics aresome of the mentioned problems. Dynamic modelling and simulation of a heat pump systemtaking all system components into consideration and validation of the model based onexperiments are suggested as the solution. This paper describes a parameter estimationapproach to variable speed heat pump unit modelling that requires a relatively low demand ofmeasured input data. The outputs of the model are a number of parameters such as totalisentropic efficiency of compressor as a function of frequency, superheat temperature andsub-cooling temperature, etc. Making use of the model provides the opportunity to evaluatethe dynamics of the whole system including building and heat source in TRNSYS.

  • 21.
    Madani, Hatef
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Lundqvist, Per
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Evaluation of the annual performance of Ground Source Heat Pump systems: A comparison between single speed and variable speed systems2011Ingår i: 23rd IIR International Congress of Refrigeration, International Institute of Refrigeration, 2011, s. 3741-3748Konferensbidrag (Refereegranskat)
    Abstract [en]

    In the present paper, modelling and simulation was carried out for a Ground Source Heat Pump (GSHP) system in the presence of all the most important interacting sub-systems such as building, ground heat source, electrical auxiliary heater, and the heat pump unit in order to make a fair and comprehensive comparison between the annual performance of on/off controlled and variable capacity systems. The annual modelling showed that dimensioning of the on/off controlled GSHP based on the peak heat demand of the building plays a significant role when two control strategies are compared: if the on/off controlled GSHP is dimensioned to cover only 57% of the peak heat demand of the building, the electrical auxiliary, which covers about 10% of the annual heating demand of the building, makes the SPF of the on/off controlled GSHP be lower than the one of the variable speed system. On the contrary, when the on/off controlled system is dimensioned to cover about 70% of the building’s peak heat demand, i.e. about 98% of the annual heat demand of the building, the SPF of the on/off controlled system can higher than the variable capacity systems.

  • 22.
    Madani, Hatef
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Lundqvist, Per
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Claesson, Joachim
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik. KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Uthålliga byggnadssystem.
    P5 – Dynamic heat pump system with capacity control2010Rapport (Övrigt vetenskapligt)
  • 23.
    Madani, Hatef
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Lundqvist, Per
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Claesson, Joachim
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Variable capacity heat pumps, modelling and simulation2008Ingår i: IEA Heat Pump conference Proceeding (2008) 9th International Energy Agency Heat Pump Conference, Academic Conferences Publishing, 2008Konferensbidrag (Refereegranskat)
  • 24.
    Madani, Hatef
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Roccatello, Erica
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    A comprehensive study on the important faults in heat pump system during the warranty period2014Ingår i: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 48, s. 19-25Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The heat pump market has become mature in many countries. There are millions of heat pumps installed worldwide. So any improvement in the installation, operation, and maintenance of heat pump systems can save a considerable amount of energy and cost, and reduce Green House Emissions to a large extent. The present study suggests a Smart Fault Detection and Diagnosis (SFDD) mechanism as the essential part of the next generation of heat pumps. A SFDD mechanism can minimize the installation and control errors, decrease the performance degradation during operation, avoid unnecessary visual inspections and components replacement, and reduce the maintenance cost and down-time of the system. To develop a SFDD mechanism, the first essential step is to obtain knowledge about the most common and expensive faults experienced by heat pumps. The heat pump manufacturers are one of the best sources to find out the most common and costliest faults occurring in heat pump systems during the first few years of their life. The present paper, as the first part of two, describes the results from a comprehensive study done on the most recent faults which were reported to some of the heat pump manufacturers in Sweden during the warranty period. The most common and the costliest faults in the Air/Air, Air/Water, Brine/Water, and exhaust air heat pumps are presented. Some of the faults such as faulty pressure switches or fans are only related to the heat pump unit, i.e. the thermodynamic cycle which facilitates the heat pumping cycle. Some of the common and expensive faults such as faulty shuttle or shuntvalve are related to the faulty components in the heating systems. Generally, the results show that faults in Control and Electronics are almost the most common and costliest faults in all types of heat pumps. Faults in Control and Electronics include any fault related to control unit, electrical faults (such as short circuit, etc.), Printed Circuit Board (PCB), display, soft starter, overcurrent and motor protection relay, etc.

  • 25.
    Madani, Hatef
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Wallin, Jörgen
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Claesson, Joachim
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Ventilation heat recovery with run around coil: System analysis and a study on efficiency improvement – Part II2009Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    In order to improve the system efficiency, a heat pump is retrofitted to a conventional run around coil ventilation heat recovery system.  The present paper aims at evaluating the annual performance of both existing run around coil system and the system to which a heat pump is retrofitted. The paper also makes a comparison between the efficiency of these two systems in two different climatic conditions. Dynamic modeling of the system was carried out over a year, using TRNSYS as the simulation tool and the results were presented for different climatic conditions. Results from the annual modeling shows that by retrofitting a well-designed heat pump unit to the system, there is a potential to increase the amount of the recovered heat up to more than 50%. By considering the energy used by the compressor of the heat pump, it can be concluded that the new system looks promising from the economic point of view and it can lead to save a large amount of energy use and money annually.

  • 26.
    Madani Larijani, Hatef
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Claesson, Joachim
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Lundquist, Per Gunnar
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Capacity control in ground source heat pump systems Part I: modeling and simulation2011Ingår i: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 34, nr 6, s. 1338-1347Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present paper, as the first part of two, suggests a method to approach the challenge of capacity control in Ground Source Heat Pumps (GSHP). The paper describes the development of a model of the system which includes several sub-models such as the heat pump unit, building, ground source, thermal storage tank, auxiliary heater, and climate. The developed computer model can be used for comparative analysis of different control methods and strategies aiming at the improvement of the system seasonal performance. With this model, on/off controlled and variable capacity GSHPs, with a single speed or variable speed pumps in the systems, can be evaluated in a wide range of operating conditions and more energy efficient methods of the system control can be found. The computer model is developed in the two environments EES and TRNSYS utilizing so-called co-solving technique.

  • 27. Mader, Gunda
    et al.
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Capacity control in air-water heat pumps: Total cost of ownership analysis2014Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 81, s. 296-304Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Adjusting capacity to changing demand by variable speed control is known to offer efficiency improvement over classical on/off control. With a total cost of ownership analysis the economic viability of both control schemes is assessed for residential air-water heat pumps operating in different climate zones. Component sizes are optimized for both control methods individually. Results show optimal compressor displacement volumes to be smaller for variable speed than for on/off control. The optimal ratio of evaporator to condenser size is smaller for the variable speed system. Variable speed control is shown to be uneconomic for space heating in warmer climate while for average climate cost-effectiveness depends on the economic framework. For colder climate variable speed control is the more profitable choice in all considered cases; savings of up to 5000 EUR compared to on/off control can be achieved within 15 years of operation.

  • 28.
    Mader, Gunda
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Bakhtiari, Hossein
    Economic optimization of component sizes in a ground source heat pump systemManuskript (preprint) (Övrigt vetenskapligt)
  • 29.
    Poppi, Stefano
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik. KTH, Centra, SeRC - Swedish e-Science Research Centre. Dalarna University, Sweden.
    Sommerfeldt, Nelson
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Bales, Chris
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Lundqvist, Per
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Techno-economic review of solar heat pump systems for residential heating applications2018Ingår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 81, s. 22-32Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Solar heat pump systems (SHPs) have been investigated for several decades and have been proven to increase the share of renewable energy and reduce electric energy demand in residential heating applications. Many review articles have been published on the subject, however literature discussing the techno-economics of different solar technologies (thermal, photovoltaic and hybrid thermal/photovoltaic) in combination with heat pumps is lacking, and thus to directly compare the merits of different SHPs is not an easy task. The objectives of this study are: a) review the different system boundaries and the main performance indicators used for assessing energetic and economic performances; b) review techno-economic studies in the literature and identify which studies give enough information and are compatible enough for making an economic inter-comparison; c) present an economic inter-comparison based on the identified systems. The results show that there is a lack of studies including an economic assessment of solar photovoltaic and heat pump systems. Additionally, there are no consistent boundaries or approaches to the study structures, making comparisons between systems difficult. In conclusion, a standardized or broadly accepted definition of technical and economic performance for SHPs is needed. Despite this, the study has shown that there are clear trends for decreasing payback times for SHPs, both solar thermal (ST) and photovoltaic (PV), with decreasing heating degree-days and with increasing solar resource.

  • 30.
    Pressani, Michele
    et al.
    Politecn Milan, Milan, Italy..
    Sommerfeldt, Nelson
    KTH.
    Madani Larijani, Hatef
    KTH.
    Investigation Of Pv/Thermal Collector Models For Use With Ground Source Heat Pumps In Transient Simulations2017Ingår i: PROCEEDINGS OF THE 11TH ISES EUROSUN 2016 CONFERENCE / [ed] Martinez, V Gonzalez, J, International Solar Energy Society , 2017, s. 1360-1371Konferensbidrag (Refereegranskat)
    Abstract [en]

    Photovoltaic-thermal (PVT) collectors are commonly designed for use in domestic hot water systems, however it can be interesting to incorporate them into ground source heat pump (GSTIP) systems. Because of the historically narrow use case, many PVT models are created with a collection of assumptions which may not apply to novel collectors designed for use in PVT+GSHP systems. The aims of this study are to review existing PVT collector models for use in TRNSYS, identify any potential error sources, and test for possible improvements. Type 560 is found to be the most promising theoretical model, however two potentially limiting features are identified; the radiation absorption model and the confinement to sheet-and-tube configurations. The absorption is tested using a recreation of Type 560 in Matlab where two alternative models developed specifically for PV modules are compared. The results show a marked increase in power during low angle, low light hours, and a 14.36% increase in electrical energy and a 10.91% for the thermal energy over the course of a day with one of the models. Collector geometry is tested by creating a ID model in EES and comparing it to several geometries in Type 560. A method of packing as many tubes as possible together is shown to give comparable results as the ID model. The results of these simulations will be compared with empirical data from currently ongoing testing.

    Ladda ner fulltext (pdf)
    fulltext
  • 31.
    Schreurs, Twan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Zottl, Andreas
    AIT Austrian Inst Technol, Sustainable Thermal Energy Syst, Vienna, Austria..
    Sommerfeldt, Nelson
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Zucker, Gerhard
    AIT Austrian Inst Technol, Sustainable Thermal Energy Syst, Vienna, Austria..
    Techno-economic analysis of combined heat pump and solar PV system for multi-family houses: An Austrian case study2021Ingår i: Energy Strategy Reviews, ISSN 2211-467X, E-ISSN 2211-4688, Vol. 36, artikel-id 100666Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With the increasing amount of building renovations in Austria, the potential increases for replacing conventional national gas heating systems with heat pumps (HP) and thereby reduce CO2 emissions particularly when combined with solar photovoltaics (PV). The Austrian subsidization scheme for HP and PV systems are different for every state, creating confusion and inconstancy for potential adopters. This study provides a parametric technoeconomic analysis of PV + HP systems to identify the critical economic parameters on profitability and make policy recommendations. A case study in Vienna is modelled using demand from the Building Model Generator and black box efficiency models for the HP and PV simulated with hourly time steps. The results show that both air-source and ground source heat pumps are currently profitable with PV under current subsidy schemes. The benefit-to-cost ratio (BCR) is highly influenced by capital costs and subsidies, however natural gas prices have the greatest influence. Increasing natural gas prices by 0.01 euro/kWh, or 17%, is enough to replace all other complicated subsidies for both HP and PV. This is equivalent to a carbon emissions price of 33 euro/ton and could result in a reduction of CO2 emissions in multi-family houses by approximately 45%-60%.

  • 32.
    Shahcheraghian, Amir
    et al.
    Department of Mechanical Engineering, École de Technologie Supérieure, Montreal, QC H3C 1K3, Canada;.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Ilinca, Adrian
    Department of Mechanical Engineering, École de Technologie Supérieure, Montreal, QC H3C 1K3, Canada;.
    From White to Black-Box Models: A Review of Simulation Tools for Building Energy Management and Their Application in Consulting Practices2024Ingår i: Energies, E-ISSN 1996-1073, Vol. 17, nr 2, artikel-id 376Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Buildings consume significant energy worldwide and account for a substantial proportion of greenhouse gas emissions. Therefore, building energy management has become critical with the increasing demand for sustainable buildings and energy-efficient systems. Simulation tools have become crucial in assessing the effectiveness of buildings and their energy systems, and they are widely used in building energy management. These simulation tools can be categorized into white-box and black-box models based on the level of detail and transparency of the model’s inputs and outputs. This review publication comprehensively analyzes the white-box, black-box, and web tool models for building energy simulation tools. We also examine the different simulation scales, ranging from single-family homes to districts and cities, and the various modelling approaches, such as steady-state, quasi-steady-state, and dynamic. This review aims to pinpoint the advantages and drawbacks of various simulation tools, offering guidance for upcoming research in the field of building energy management. We aim to help researchers, building designers, and engineers better understand the available simulation tools and make informed decisions when selecting and using them.

  • 33.
    Sommerfeldt, Nelson
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Beltran, Francisco
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    High Market Potential Applications for PVT with Heat Pumps2020Ingår i: PROCEEDINGS OF THE ISES EUROSUN 2020 CONFERENCE - 13TH INTERNATIONAL CONFERENCE ON SOLAR ENERGY FOR BUILDINGS AND INDUSTRY / [ed] Charalambides, A Streicher, W Mugnier, D, International Solar Energy Society (ISES) , 2020, s. 551-557Konferensbidrag (Refereegranskat)
    Abstract [en]

    Within the heat pump sector, there are applications where photovoltaic/thermal (PVT) collectors can offer greater value with lower investment costs than the current alternatives. The first is ground source heat pumps (GSHP) with under dimensioned boreholes. The second is a solar source heat pump (SSHP) where the PVT collectors are a replacement for the traditional air heat exchanger in an air source heat pump (ASHP). Complete systems models for a multi-family house are simulated in TRNSYS to determine seasonal performance factors (SPF), which are then compared technically and economically to each respective alternative. A 156 m(2) PVT array is capable of improving the SPF of a degraded GSHP by 30%, the same gains as drilling additional boreholes but at a lower cost. The SSHP with a 235 m(2) PVT array can reach an SPF of 2.6, comparable to the performance of an ASHP, but has the cost of a GSHP. Already today, PVT can economically compete with borehole drilling for GSHP and the SSHP concept shows enough market potential to warrant investment and development towards broader adoption.

  • 34.
    Sommerfeldt, Nelson
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Lemoine, Ida
    Beteendelabbet AB.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    A User-Centered Design Approach to Identify Behavioral Biases in the Adoption of Solar PV by Households2021Ingår i: 6th European Conference on Behaviour Change for Energy Efficiency / [ed] Xianli Zhu and Gabriela Prata Dias, Copenhagen, 2021, s. 134-137Konferensbidrag (Refereegranskat)
    Ladda ner fulltext (pdf)
    BEHAVE2020-2021_SommerfeldtLemoineMadani_UserCenteredDesignInSolarPV
  • 35.
    Sommerfeldt, Nelson
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Lemoine, Ida
    Beteendelabbet AB, Stockholm, Sweden..
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Hide and seek: The supply and demand of information for household solar photovoltaic investment2022Ingår i: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 161, s. 112726-, artikel-id 112726Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Buildings provide an ideal platform for solar photovoltaics (PV) towards sustainable development goals, and the decision to invest in PV lies predominantly with building owners. Information delivery is critical for the diffusion of innovations, and this study aims to improve the quality of information for household PV investors in Sweden. A User Journey Mapping approach is applied with a combination of semi-structured interviews and a review of online solar calculators. The results show that despite a rapid growth in the quantity of information there is still a gap between demand and supply due to the lack of clarity and trustworthiness of information. This is clearly demonstrated in the review of online calculators, which show a high variance in results. Payback time, for example, ranged from 7 to 18 years for a single test case. The information gap can be closed by creating neutral, non-commercial online information sources that focus on transparency and education where household investors can validate supplier offers and analyses. The PV industry risks eroding trust in the market, which will likely slow adoption by the early majority and hinder sustainability goals.

  • 36.
    Sommerfeldt, Nelson
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Improved methodology for determining the value of energy from distributed renewables using statistical analysis combined with normative scenarios2014Ingår i: Energy Procedia / [ed] J. Yan, DJ. Lee, SK. Chou, U. Desideri, H. Li, Elsevier, 2014, Vol. 61, s. 1089-1092Konferensbidrag (Refereegranskat)
    Abstract [en]

    The financial benefits of a distributed electric generation facility cannot be calculated without an expectation of the electricity's market value. Prediction of long-term future prices is a difficult but mandatory task, which is often reduced to constant annual prices with steady annual growth rates. This study provides a methodology for predicting electricity prices at an hourly resolution for long-term analysis, using the Swedish case as an example. It includes a statistical examination of historical data inspired by the meteorology sector to create a “typical year” of hourly price values. Future prices are calculated by applying annual rate changes to the typical year curve, using a monthly resolution to allow for seasonal variations. Rate changes are predicted using historical trends and current market conditions for near-term prices, and a normative scenario for mid- to long-term prices. The resulting methodology can be used in part or whole for any market in which historical data is available and a normative scenario created.

    Ladda ner fulltext (pdf)
    SommerfeldtMadani-Final
  • 37.
    Sommerfeldt, Nelson
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    On the use of hourly pricing in techno-economic analyses for solar photovoltaic systems2015Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 102, nr SI, s. 180-189Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of hourly prices in distributed photovoltaic (PV) techno-economic analysis is rare, but may become necessary as time-of-day retail pricing becomes more common. A methodology is presented for selecting an hourly price curve suitable for long-term analysis, called the typical price year (TPY), which is based on the methodology for TMY weather data. Using a techno-economic analysis with annual revenues and net present value as indicators, a TPY curve for the Swedish market is validated and then compared to 18 price simplification methods to determine the error introduced by the use of non-hourly prices. Results show that the TPY method produces a curve which accurately represents long term pricing trends, but using a static annual mean introduces minor revenue errors of 1.3%. This suggests the TPY may not be necessary in the Swedish market, but further analysis of the method is suggested for other markets.

    Ladda ner fulltext (pdf)
    fulltext
  • 38.
    Sommerfeldt, Nelson
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    REVIEW OF SOLAR PV/THERMAL PLUS GROUND SOURCE HEAT PUMP SYSTEMS FOR EUROPEAN MULTI-FAMILY HOUSES2016Ingår i: Eurosun 2016, 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    The combination of photovoltaic-thermal (PVT) hybrid modules with ground source heat pumps (GSHP) has the potential to increase renewable fractions of heating, cooling and power generation in buildings. The concept benefits each component in the system; the solar collector can be more efficient; collected heat can be stored in the boreholes and recovered in both short and long term; and the elevated temperatures of the boreholes improves the efficiency of the heat pump. System optimization is challenging due to the number of possible configurations, options in component designs and system control, and the close interrelation of performance between components. This study presents several system configurations which are designed to be a balance of performance, practicality, and cost. The designs are based on a state-of-the-art literature review from multiple fields (solar collectors, heat pump controls, seasonal thermal storage, and solar assisted heat pumps) and consultations with heat pump and PVT collector manufacturers.

  • 39.
    Sommerfeldt, Nelson
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    A Techno-Economic Comparison between PV and PVT Integrated Ground Source at Pumps for Multi-Family Houses2018Ingår i: Proceedings of the ISES Eurosun 2018 conference / [ed] Haberle, A, International Solar Energy Society, 2018, s. 901-910Konferensbidrag (Refereegranskat)
    Abstract [en]

    As the demand for sustainable energy technologies grows, solar photovoltaics (PV) and heat pumps are increasingly being used in buildings. Hybrid PV-thermal (PVT) collectors have been researched for decades, but have not yet had success in the market. This study combines PVT and ground source heat pumps (GSHP) in a series connection for a multi-family house, and compares the technical and economic performance to GSHP and PV+GSHP systems. A complete systems model in TRNSYS is used for the solar heat pump system, and climate and economic boundary conditions come from the Swedish market. The results show that reducing the borehole length and/or spacing with no or a limited loss of efficiency is the greatest benefit of adding PVT, however a fully sized borehole field with PV is found to be the lowest cost design option. In systems with poor efficiency and high auxiliary boiler use, the addition of PVT can be the lowest cost option but is not preferable to the PV+GSHP when space is not a limitation. The reduction in borehole field area for a given heat pump efficiency is notable since many multi-family homes cannot install GSHP due to a lack of drilling space. PVT+GSHP systems could offer a new, low-carbon heating alternative for buildings previously outside of the heat pump market.

    Ladda ner fulltext (pdf)
    SommerfeldtMadani2018_PVandPVT-GSHP_Eurosun2018
  • 40.
    Sommerfeldt, Nelson
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Ground Source Heat Pumps for Swedish Multi-Family Houses: Innovative Co-Generation and Thermal Storage Strategies2018Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Bergvärme har en relativt liten marknadsandel i flerfamiljshus, delvis på grund av det begränsade markutrymmet tillgängligt för borrning. Den snabbt växande marknaden för solceller (PV) ger en ny möjlighet för bergvärme genom att kunna fungera som sekundär värmekälla och regenerera marken via en värmeväxlare monterad på baksidan av PV-panelen. Hybrid PV / termiska kollektorer, kallad PVT, har högre effektivitet än PV, men har också ett betydligt högre pris.

    Det primära målet för detta forskningsprojekt har varit att identifiera den tekniska och ekonomiska potentialen för PVT-integration i flerfamiljshus med bergvärme-system. Detta uppnås genom en detaljerad teknisk analys, dynamisk modellering av hela systemet, noggrann utformning av testinstallationen och en kvalitativ bedömning av kommersiella möjligheter.

    Resultaten visar att PVT-kollektorerna kan kompensera för en betydande underdimensionering av borrhålslagret, men att denna lösning endast är ekonomisk under specifika förhållanden. Ett fall är där värmepumpen periodvis stängs av på grund av låga köldbärartemperaturer och systemet istället körs på direktelvärme. Besparingarna från borrningen och ökningen av årsvärmefaktorn (SPF) är i dessa fall tillräckliga för att motivera extrakostnaden för PVT. I de fall där en värmepump har körts i flera år och marktemperaturerna är låga kan PVT lyfta och stabilisera temperaturerna till en lägre kostnad än ytterligare borrning (om detta över huvud taget är möjligt). I de fall där tillgång till mark inte är en begränsning är det högsta effektivitets- och lägsta kostnadsalternativet att göra ett borrhålslager av traditionellt storlek och bara installera ett vanligt PV system.

    Att integrera PVT med bergvärme är relativt enkelt jämfört med traditionella solvärmesystem. Det behövs inga förändringar i varmvattentank eller uppvärmningssystem, endast en PVT-värmeväxlare införd i borrhålskretsen, vilket gör integration och eftermontering enklare. Att möjliggöra för ett större antal flerfamiljshus att installera bergvärme kan minska energikostnaderna, primärenergianvändningen och koldioxidutsläppen. Måtten för moderna PVT-moduler är samma som för PV och PVT kvalificerar för närvarande för statligt stöd, vilket ger möjligheter för tillverkare och installatörer att expandera sina produktutbud.

    PVT har visat sig kunna hjälpa till att öppna upp den svenska flerfamiljshusmarknaden för bergvärme och fortsatt forskning bör fokuseras på detaljerade lösningar för utformningen, empirisk bestämning av prestanda och reduktion av kostnaderna.

    Ladda ner fulltext (pdf)
    SommerfeldtMadani2018_SolarHeatPumpsForMFH-EffsysExpand
  • 41.
    Sommerfeldt, Nelson
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    In-depth techno-economic analysis of PV/Thermal plus ground source heat pump systems for multi-family houses in a heating dominated climate2019Ingår i: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 190, s. 44-62Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The electrification of buildings is a promising pathway to the decarbonization of cities. This is a parametric study of the technical and economic performance of ground source heat pump (GSHP) systems with series connected solar PV/thermal (PVT) collectors. The focus is on multi-family houses (MFH) in the heating dominated climate of Sweden, where land restrictions for boreholes or noise restrictions on air heat exchangers limit the heat pump market. System efficiency and lifecycle cost results are generated using a holistic and detailed systems model in TRNSYS with 20 year simulations. The results show that PVT can reduce borehole length by 18% or spacing by 50% while maintaining an equivalent seasonal performance factor to systems without PVT. The cost for PVT + GSHP systems is higher than a traditionally designed PV + GSHP, however this does not take into account the value of the land area saved by PVT, which can be up to 89%. The reduction in land enabled by PVT has the potential to increase penetration of GSHP in MFH and promote solar energy diffusion in high latitude markets.

  • 42.
    Sommerfeldt, Nelson
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Revisiting the techno-economic analysis process for building-mounted, grid-connected solar photovoltaic systems: Part one - Review2017Ingår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 74, s. 1379-1393Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The market for solar photovoltaic systems is growing rapidly into a mature industry, while at the same time policies which have spurred the growth (e.g. feed-in tariffs or net metering) are beginning to fade away. These policies made techno-economic studies relatively simple for engineers, analysts, and owners, however investing in a deregulated market requires more advanced tools than the traditional engineering economics which dominate the literature. The objective of part one in this paper is to catalogue and critique the range of methods and models relevant to techno-economic analysis for PV systems in the context of distributed, grid-connected buildings. This is accomplished by; developing a system modeling framework for prosumer PV investment analysis, reviewing relevant energy, economics, and finance literature to identify mathematical models which can be applied, and cataloging the use of the reviewed techniques in the relevant literature. Also included is a qualitative discussion of the benefits and practicality of the review techniques, where Monte Carlo analysis is highlighted as an exemplary method. This review is useful as a reference for analysts, researchers, and engineers developing PV integration solutions for building energy systems in a post early adopter PV market.

  • 43.
    Sommerfeldt, Nelson
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Revisiting the techno-economic analysis process for building-mounted, grid-connected solar photovoltaic systems: Part two - Application2017Ingår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 74, s. 1394-1404Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Part One in this two part paper identified Monte Carlo analysis as an improved approach over traditional deterministic techno-economic methods for solar PV prosumers in deregulated markets. In this paper a novel Monte Carlo methodology is described and demonstrated through a case study for the Swedish residential sector, which includes a review of relevant market, climate, and policy conditions, their use in determining inputs, and the probabilistic results. The probability of profitability (PoP) is introduced as an indicator in conjunction with result distributions. The results show that under current policy conditions, Swedish PV investors with well positioned buildings have a 71% chance of making a 3% real return on investment, and virtually no chance of losing their original investment. Without subsidies the PoP drops to 8%. In none of the simulated cases was any of the original investment lost. The PoP is most sensitive to the capital subsidy and the uncertainty of market based, long-term support is less critical to the chances of a successful investment. Given the current market conditions, Swedish PV prosumers can expect a return on investment. The decision to install will also depend on the probability of achieving their desired profitability, which Monte Carlo analysis quantifies well.

  • 44.
    Song, Yang
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Peskova, Monika
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Rolando, Davide
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Zucker, Gerhard
    Sustainable Thermal Energy Systems, AIT Austrian Institute of Technology, Giefinggasse 2, A-1210 Vienna, Austria.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik. Sustainable Thermal Energy Systems, AIT Austrian Institute of Technology, Giefinggasse 2, A-1210 Vienna, Austria.
    Estimating electric power consumption of in-situ residential heat pump systems: A data-driven approach2023Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 352, artikel-id 121971Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    International Energy Agency predicts that the global number of installed heat pumps (HP) will increase from 180 million in 2020 to approximately 600 million by 2030, covering 20% of buildings heating needs. Electric power consumption is one of the main key performance indicators for the heat pump systems from techno-economic perspective. However a common issue prevalent in many existing heat pumps is the lack of electric power measurement. The modern installations might be equipped with electric power measurement sensors but this comes at a higher system cost for the manufacturers and end-users. The primary objective of this work is to propose a virtual measurement for estimating power consumption, thereby eliminating the need for field measurement of power for heat pumps. To achieve the objective, a data-driven approach is proposed. Firstly, the in-situ data is preprocessed through data merging, cleaning, and normalization. Then, input features are pre-selected using Spearman correlation coefficients, and further refined by addressing multicollinearity problem. Following this, Extreme Gradient Boosting (XGBoost) models and polynomial models are developed by considering different features as inputs. All models are finally validated against the in-situ data from multi-units of ground source heat pump (GSHP) and air source heat pump (ASHP) installations. The results showed that the electric power consumption of GSHP can be estimated with high accuracy (99% for R2, 10 W for MAE, and 1% for MAPE) through generic data-driven models using only four easy-to-measure input features. Taking three input features as inputs for ASHP generic model, the accuracy can be reached to 83% for R2, 125 W for MAE, and 9% for MAPE. The method presented in this paper can be applied to estimate power consumption of millions of heat pumps and consequently add a significant value as well as provide different types of services, such as cost-saving benefits for manufacturers and end-users, flexibility services for aggregators and electricity grids.

  • 45.
    Song, Yang
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Rolando, Davide
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Avellaneda, Javier Marchante
    Univ Politecn Valencia, Inst Univ Invest Ingn Energet, Camino Vera S-N,Ed 8E Semisotano, Valencia 46022, Spain..
    Zucker, Gerhard
    Austrian Inst Technol, Sustainable Thermal Energy Syst, Giefinggasse 2, A-1210 Vienna, Austria..
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik. Austrian Inst Technol, Sustainable Thermal Energy Syst, Giefinggasse 2, A-1210 Vienna, Austria..
    Data-driven soft sensors targeting heat pump systems2023Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 279, s. 116769-, artikel-id 116769Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of smart sensors, low cost communication, and computation technologies enables continuous monitoring and accumulation of tremendous amounts of data for heat pump systems. But the measurements, especially for domestic heat pump, usually suffer from incompleteness given technical and/or economic barriers, which prevents database of measurements from being exploited to its full potential. To this end, this work proposes a data-driven soft sensor approach for compensating multiple missing information. The soft sensors are developed based on an ANN model, an integrated multivariate polynomial regression model and empirical model by considering different constrains like data and information availability during model establishing process. All the three models have been validated against the data from a field test installation, and showed good performance for all the compensated variables. Of the three models, the ANN model shows the best performance for all soft sensors, but it has the highest requirement for additional resources to collect training data. While the integrated multivariate polynomial regression model demonstrates excellent accuracy for the majority of soft sensors with manufacturers' subcomponent data which needs no extra cost. Even though empirical model is not as accurate as the other two models, it still performs good accuracy with limited information from performance map. The methods developed in the present study paves the way for available measured data in thousands of installations to be fully utilized for innovative services including but not limited to: improved heat pump control strategies, fault detection and diagnosis, and communication with local energy grids.

  • 46. Sovacool, Benjamin K.
    et al.
    Cabeza, Luisa F.
    Pisello, Anna Laura
    Colladon, Andrea Fronzetti
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Dawoud, Belal
    Martiskainen, Mari
    Decarbonizing household heating: Reviewing demographics, geography and low-carbon practices and preferences in five European countries2021Ingår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 139, artikel-id 110703Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    What commonalities are there in sustainable or unsustainable heating practices in five high-income, high-emitting western European countries? What preferences do a nationally representative sample of the public in these countries hold towards low-carbon options? It is imperative that climate policy researchers and practitioners grapple with the difficulty of decarbonizing heat, which remains the largest single end-use service worldwide and which accounts about half of total final energy consumption. Based on a comparative assessment of five representative national surveys in Germany (N = 2009), Italy (N = 2039), Spain (N = 2038), Sweden (N = 2023), and the United Kingdom (N = 2000), this study explores the demographics and geography of household heat decarbonisation in Europe. By analyzing our country level data as well as our combined sample of 10,109 respondents, it investigates how people conceive of the purposes of low-carbon heat, their preferences for particular forms of heat supply, and their (at times odd) practices of heat consumption and temperature settings. Grounded in its original data, the study organizes its findings inductively across the five themes of literacy (heating knowledge, awareness and control), sustainability (heating practices, dynamics and conflicts), temperature (heating satisfaction and preferences), desirability of change (low-carbon heating priorities, business models and trust), and culture (country and national variation). The study also explores intersections between these dimensions, using multivariate analysis, as well as how preferences differ according to varying types of actors as well as geography and space.

  • 47.
    Su, Chang
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Palm, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Heating solutions for residential buildings in China: Current status and future outlook2018Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 177, s. 493-510Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With continuing of urbanization, improving of life quality as well as combating against air pollution, China is facing comprehensive challenges to supply modem clean heating to a majority of its citizens. For space heating solutions, currently in urban areas of north China, coal based district heating is prevalent. In urban areas of south China, distributed heating solutions are used. In rural areas, de-centralized coal stoves and biomass stoves are still commonly used. As renewable building heating solution, ground source heat pumps are installed for large scale applications. Building floor areas heated by ground source heat pumps increased tremendously during past ten years. Air source heat pump is being promoted in north Chinese rural areas as part of coal to clean heating project. Solar water heater and electric water heater for domestic hot water supply is widely used in north China and gas water boiler is widely used in south China. A series of policies have encouraged clean fossil fuel district heating in north China. National development plans are also supporting and subsidizing renewable heating technology such as heat pumps. Different building heating technologies have their own advantages and disadvantages from techno-economic and environmental perspectives. The choice of building heating solutions for different geolocations of China is strongly affected by spatial parameters such as local climate condition, population distribution, natural resource availability etc. Therefore, a spatial data analysis method is essential to help stakeholders decide proper building heating solutions in different parts of China by key performance indicators reflecting lower primary energy use, economic affordability and lower environmental impact.

  • 48.
    Su, Chang
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Liu, Hua
    Wang, Ruzhu
    Palm, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Sea water heat pumps in China: A spatial analysis2020Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 203, artikel-id 112240Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fossil fuel based building space heating and cooling contribute to more than 10% total final energy consumption in China. Consequent carbon dioxide and air pollutants emissions bring about atmospheric pressure and associated respiratory diseases. Seawater heat pumps as a candidate sustainable building space heating and cooling solution can alleviate such environmental pressure since China has a long coastline and many coastal cities have the possibility for seawater heat pump implementation. However, stakeholders are still suffering from insufficient understanding of seawater heat pumps feasibility in different coastal cities of China from techno-economic, environmental and geographical perspectives. This paper proposes a systematic method to evaluate seawater heat pump potential in different locations of China considering various local spatial parameters in the source and sink side of the energy system. A key performance indicator system is introduced to quantitatively analyze the relative advantages and disadvantages of applying seawater heat pumps compared with status-quo systems. Quantitative evaluation results show that seawater heat pumps have a higher potential in north Chinese coastal cities from techno-economic point of view when compared with existing heating and cooling systems. Environmentally, seawater heat pumps have to reach a critical seasonal coefficient of performance value to guarantee its potential in carbon emissions saving. In south Chinese coastal cities, seawater heat pumps have to reach a more satisfactory system efficiency and a more competitive system cost in order to exploit its full advantages over status-quo systems from techno-economic perspectives. Environmentally, seawater heat pumps are more attractive than competing technologies in south cities. Also, north Chinese cities are geographically more feasible for seawater heat pumps applications compared with south cities.

    Ladda ner fulltext (pdf)
    fulltext
  • 49.
    Su, Chang
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Palm, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    A Systematic multi-criteria assessment infrastucture for residential building heating technologies in China2019Ingår i: 11th International Conference on Applied Energy 2019, 2019, artikel-id 0830Konferensbidrag (Refereegranskat)
    Abstract [en]

    China nowadays faces comprehensive challenges on supplying modern clean space heating to a majority of its citizens. Various building space heating technologies are implemented throughout north and south China. However, investors and policy makers are suffering from a lack of a systematic assessment tool to evaluate which heating technology to choose based on unique local conditions from techno-economic and environmental perspectives. This paper fulfills such research gap by proposing a multi-criteria assessment infrastructure to assist relative stakeholders evaluate potentials of different space heating technologies. The proposed infrastructure is multi-disciplinary and requires to handle a large amount of data from various sources, which can well reflect the feasibility of building space heating technologies systematically.

    Ladda ner fulltext (pdf)
    fulltext
  • 50.
    Su, Chang
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Madani Larijani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Palm, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Building heating solutions in China: A spatial techno-economic and environmental analysis2019Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 179, s. 201-218Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fast urbanization process and promotion of life standard in China requires a great amount of energy input in building heating sector. North China now faces challenges of upgrading existing fossil fuel based high emission district heating systems into more environmental friendly heating systems. South China is discussing to choose proper building heating solutions for new and existing buildings which lack proper heating facilities. Renewable heating technologies such as ground source heat pump and air source heat pump are candidates to upgrade traditional heating solutions such as fossil fuel boilers and electric heaters. In order to find the most feasible building heating solution for different geolocations of China, this paper proposes a spatial data based techno-economic and environmental analysis methodology to fulfill such research gap. Case studies are carried out in two selected cities by using proposed methodology. Evaluation model shows that, heat pumps is quite competitive in south China compared with electric heaters, whereas in north China heat pumps have to reach several preconditions to be competitive with coal boiler district heating system under current techno-economic and environmental situations. In north China, a heat pump should reach a minimum seasonal coefficient of performance of 2.5-3.7 (for ground source heat pump) or 2.7-3.0 (for air source heat pump) to become CO2 and PM2.5 emission neutral as well as economically competitive compared with coal boiler district heating system. The advantage of proposed methodology is its simplicity in execution and could be repeated to other areas as the data required are available.

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