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  • 1.
    Arias, Jaime
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Effektivare butikskyla: Värme ur kylanläggningar samt system med flytande kondensering, Aktiviteter 20062007Report (Other academic)
  • 2.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Adiabatic two-phase flow hydraulic performance in a compact brazed plate heat exchanger2007In: Heat SET: Heat Transfer in Components and Systems for Sustainable Energy Technologies / [ed] Thonon, 2007Conference paper (Refereed)
  • 3.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Beräkningsmetoder för årsvärmefaktor för värmepumpsystem för jämförelse, systemval och dimensionering2010Report (Other academic)
  • 4.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Butiken i kyllabbet på IUC har öppnat2006In: ScanRef, ISSN 0284-0758, no 4, p. 44-47Article in journal (Other (popular science, discussion, etc.))
  • 5.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    CERBOF Projekt no. 72: Utfall och metodutvärdering av energideklaration av byggnader2011Report (Other academic)
  • 6.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Correction of Logarithmic Mean Temperature Difference in a compact brazed plate evaporator assuming heat flux governed flow boiling heat transfer coefficient2005In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 28, no 4, p. 573-578Article in journal (Refereed)
    Abstract [en]

    The heat transfer in heat exchangers is commonly calculated using the concept of Logarithmic Mean Temperature Difference (LMTD). As is well known this approach is only valid for counter-current and co-current heat exchanger configurations. For other configurations, corrections for the deviation from pure counter-current are introduced. From any standard text book in heat transfer it may be found that the LMTD approach may also be used if condensation and evaporation occurs in the heat exchanger. The purpose of the present paper is to investigate if the LMTD approach can be used in a compact brazed plate evaporator. It will be shown through integration of the governing equations that the LMTD approach indeed may be used for practical cases, even though deviations occur at small logarithmic mean temperature differences. The article presents suggestions on the correction factor (F) needed under some simplified assumptions in a compact brazed plate heat exchanger operating as an evaporator for heat pump and refrigeration applications.

  • 7.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    En litteraturstudie om klimatets inverkan på kyleffekt och avfrostningsbehov i livsmedelsbutiker2005Report (Other academic)
  • 8.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Kombisystem: uthållig uppvärmning av mindre fastigheter2008In: Energi & Miljö, ISSN 1101-0568, no 12, p. 68-72Article in journal (Other academic)
  • 9.
    Claesson, Joachim
    KTH, Superseded Departments, Energy Technology.
    Literature Survey, relevant to compact brazed plate heat exchangers as evaporators in heat pump system2004Report (Other academic)
  • 10.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Local flow boiling experiments with refrigerant R134a in compact brazed plate heat exchanger2007Conference paper (Other academic)
  • 11.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Performance Evaluation of Combined Heat Sources for Innovative Heat Pumps: Ground Source Combined With an Air Coil, Paper ID 6502013Conference paper (Refereed)
    Abstract [en]

    A significant amount of the Swedish single family houses have installed a ground source heat pump as primary energy source. Many of these installed heat pumps are due for replacement and the new installed heat pumps are generally more efficient. Thus, they extract more heat from the ground at a given heat load of the building. This fact combined with the early “rule of thumb” used by Swedish installers for sizing the borehole length means that many boreholes now are slightly undersized in terms of length.One obvious remedy is to drill some additional meters to the existing borehole. Other alternatives exist to offset this situation as well and two of these are that the borehole is assisted by either a solar collector or an outside air heat collector, similar type used for air-to-air heat pumps. The effect of such a measure is that less energy is extracted from the ground during the heating season, and the heat pump may operate at higher heat source temperatures. In addition, it may prevent or at least delay freezing of the borehole, which may occur late of the heating season for some installations.The present paper investigates the performance of such system and to compare the outcome of these three systems in terms of annual energy extraction rate from the ground. The results indicate that the proposed system indeed may offset the additional heat extraction that a new more efficient heat pump would otherwise cause.

  • 12.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Performance of compact brazed plate heat exchanger operating as condenser in domestic heat pump system: An experimental investigation2005In: International Energy Agency Heat Pump Conference: Global Advances in Heat Pump Technology, Applications, and Markets, 2005Conference paper (Refereed)
  • 13.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Plattvärmeväxlare: Hur kan jag räkna enfasvärmeövergångstal i dessa?2005Report (Other academic)
  • 14.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Plattvärmeväxlare som förångare, jämförelse mellan förångare med och utan fördelningsanordning2002In: Kyla, no 3, p. 41-43Article in journal (Other academic)
  • 15.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Slutrapport Etapp 1: Energieffektiv Kyla – Effektivare Styrning, Övervakning och Systemlösningar2006Report (Other academic)
  • 16.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    The influence of brine flow on the flow boiling refrigerant heat transfer coefficient in a compact brazed plate heat exchanger2005In: International Journal of Heat Exchangers, ISSN 1524-5608, Vol. 6, no 1, p. 35-54Article in journal (Refereed)
    Abstract [en]

    The present article investigates the heat transfer coefficient on the refrigerant side in an compact brazed plate heat exchanger used as evaporator with different brine flows. The experimental equipment consisted of a test rig, simulating a domestic heat pump. Two different heat loads were tested, 5 kW and 10 kW, which corresponds to approx. 2.5 kW/m2 and 5.0 kW/m 2. The inlet quality to the evaporator was kept within 0.18 - 0.20. The pressure was kept within 2.93 - 2.97 bar(a) and R134a was used as refrigerant. The experiment showed for both heat loads a significant increase in the refrigerant area averaged heat transfer coefficient with increasing brine flow. It may be concluded that the temperature profile on the brine side has a significant influence on the refrigerant area averaged heat transfer coefficient. It is suggested that the higher wall superheat on the refrigerant side near the inlet of refrigerant is enhancing the heat transfer.

  • 17.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Thermal and hydraulic characteristics of brazed plate heat exchangers - Part I: Review of single-phase and two-phase adiabatic and flow boiling characteristics2005In: ASHRAE Transactions 2005, Vol 111, Pt 1, 2005, Vol. 111, p. 822-833Conference paper (Refereed)
    Abstract [en]

    This paper reviews the status of research reported in the open literature on plate heat exchangers, operating in single-phase and two-phase adiabatic and flow boiling applications. The review has been made as apart of an ongoing study aimed at enhancing the efficiency of heat transfer in plate heat exchangers used as evaporators in small heat pumps. It constitutes the background for the report of the activities within the project, given in part two of the present article. In order to obtain a complete picture of the performance of a plate heat exchanger operating as an evaporator, it is as important to have knowledge of the single-phase characteristics as it is to have knowledge of the flow boiling characteristics. The review shows that single-phase flow is quite well understood, even if the influence of the many geometric parameters is still under discussion. It also shows that there is still a controversy concerning which mechanism is dominant in flow boiling: convective evaporation or nucleate boiling.

  • 18.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Thermal and hydraulic characteristics of brazed plate heat exchangers - Part II: Current research on evaporators at KTH2005In: ASHRAE Transactions 2005, Vol 111, Pt 1, 2005, Vol. 111, p. 834-845Conference paper (Refereed)
    Abstract [en]

    This paper summarizes recent research on plate heat exchangers used as evaporators in domestic heat pumps and refrigeration systems, carried out at the Royal Institute Of Technology, Sweden. The investigations have been focusing on issues relevant to the performance and to parameters influencing the performance for the application in mind. Thus, the adiabatic pressure drop in a plate heat exchanger has been investigated and a new correlation is suggested, based on the classical approach by Lockhart-Martinelli and the correlation by Chisholm. The boiling section heat transfer coefficient was experimentally determined using TLC measurements. The resulting heat transfer coefficient was then plotted against mass flux and heat flux in order to investigate the relative importance of the two parameters. As it was found that the heat flux correlated the data much better than the mass flux, the applicability of using the LMTD assuming a heat flux-governed flow boiling correlation was investigated next. In addition, since the heat transfer coefficient seemed dependent on heat flux (wall superheat) the impact of different brine mass flow rates and brine temperature profiles was investigated. Further the possible improvement of running the evaporator in co-current configuration was investigated. The influence of geometry (chevron angle) and of using different inlet refrigerant flow distributor devices on the performance of a plate heat exchanger was also investigated.

  • 19.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Thermal and hydraulic performance of compact brazed plate heat exchangers operating as evaporators in domestic heat pumps2005Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    This thesis investigates the performance of compact brazed plate heat exchangers (CBE) operating as evaporator in heat pump applications. The thesis, and the performances investigated, has been divided into three main sections; One zone evaporator performance; Two zone evaporator performance; and finally Local performance.

    The 'One zone evaporator performance' section considers the evaporator as one "black box". It was found that "approaching terminal temperatures" were obtained as low overall heat flux is employed. It was also found that the total area averaged film heat transfer coefficient was affected by changes of the brine mass flow rate. This indicates that the widespread Wilson plot method may not be used to determine flow boiling heat transfer coefficients. Further, it seems that co- and counter-current flow configuration performs equally well if the superheat is kept low. A numerical simulation of the above investigations indicates that a nucleate boiling model better predicts the performance compared to a convective evaporation model. Finally, the significant impact of the refrigerant inlet distributor design was illustrated using several CBEs with different inlet geometries but with identical heat transfer surfaces.

    The 'Two zone evaporator performance section' considers the evaporator as two "black boxes", i.e. the boiling and superheating boxes. Thermochromic liquid crystals (TLC) was used to determine the boiling heat transfer area. The resulting flow boiling heat transfer coefficient was found to correlate with heat flux. The superheated heat transfer area was then estimated using single phase correlations. It was observed that the TLC measurements and the predicted superheating area did not agree. Possible causes for this deviation were discussed. The most likely explanation found was the presence of mist flow at the higher vapor quality range in the boiling section of the evaporator.

    The 'Local Performance' section considers local pressure drop and flow boiling heat transfer. The Chisholm parameter was found not to be a constant and was found to correlate well with the kinetic energy per volume. The resulting predictions of the pressure drop were better than ± 10%.

    The resulting local flow boiling heat transfer coefficient, at different vapor quality, mass flux and heat flux, was compared to flow boiling correlations available in the literature. It was found that the saturated nucleate pool boiling correlation by Cooper (1984) and narrow channel flow boiling correlations (Tran 1999, Lazarek and Black 1982) predicted the experimental data better than several traditional flow boiling correlations, developed for larger tubes.

  • 20.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    TriGen: Uthållig förnybar uppvärmning av små och medelstora hus2008Report (Other academic)
    Abstract [sv]

    Föreliggande projekt var en förstudie för utvärdering av uthålligt uppvärmningssystem för småoch medelstora bostadsfastigheter. Uppvärmningssystemen som undersöktes innehöll ettkombisystem bestående av en värmemotor från ComPower för produktion av värme, för drivningav värmepump samt generering av elektricitet. Ett annat alternativ bestod av en värmemotor förelgenerering där motorns spillvärme driver en värmedriven värmepump. Tre typer avvärmepumpar undersöktes. En av dess är en mekanisk värmepump med uteluft som värmekälla,en annan använder IVTs ytjordsstaketlösning som värmekälla. Den värmedrivna värmepumpenär en konstruktion av ClimateWell.Resultaten från projektet visar att föreslaget system med kombinerat minielkraftverk eldad medpellets kombinerat med en mekanisk värmepump utnyttjar bränslet mest effektivt. Vid balansmellan producerad el i minikraftverket och förbrukad energi i kompressorn utnyttjas bränslet tillmer än 155 %. Anledningen till det är, som för alla värmepumpssystem, att gratis energi frånomgivningen utnyttjas.Undersökning kring tillgänglig teknik för realisering av systemet visar att alla ingåendekomponenter som krävs finns att tillgå (Pelleteldad stirlingmaskin), alternativt finns påprototypstadiet (pelleteldad mikrogasturbin). Avseende värmepumpen är den mest ekonomiskatypen att använda en s.k. uteluft/vatten-värmepump, d.v.s. att värmepumpen tar sin energi frånuteluften och avger den till ett vattenburet radiatorsystem inne i byggnaden. Det finns fleratillgängliga fabrikat att välja bland.Vad gäller minielkraftverk finns det ett svenskt företag som inom kort ämnar serietillverka enpelleteldad mikrogasturbin avsedd för småhus, som då kan producera både elektricitet ochvärme. Det finns även alternativ till detta internationellt, t.ex. säljs pelleteldade mikroelkraftverkbaserat på en stirlingmotor på den europeiska marknaden. Utöver detta finns mängder medförbränningsmotorer som åtminstone i några fall torde gå att elda med ”biodiesel”. Se Tabell 1 för typiska data för pelleteldade mikroelkraftverk.

  • 21.
    Claesson, Joachim
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Afghani, Mohsen
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Influence of large temperature difference in a compact brazed plate evaporator with low overall heat flux2003In: / [ed] J.M. Corberán, R. Royo, 2003, p. 33-37Conference paper (Refereed)
  • 22.
    Claesson, Joachim
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Antin, Karina
    Arias, Jaime
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Wallin, Jörgen
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Utvärdering av värmepumpar som attraktivt del i åtgärder i 50-, 60-, 70-tals inklusive även miljonprogrammet sett ur ett tekno-ekonomiskt perspektiv2010Report (Other academic)
  • 23.
    Claesson, Joachim
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Forsén, Martin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Capacity control of a domestic heat pump: Part 1 – Performance of the heat pump and its components2002Conference paper (Refereed)
  • 24.
    Claesson, Joachim
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Hill, Peter
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Björk, Folke
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Slutrappport - Värmestugan – effektiviseringskoncept av bergvärme/solpanel/energilager - Utvärdering KTH: Diarienummer: 2013-0066552016Report (Other academic)
    Abstract [sv]

    Föreliggande projekt syftar till att utvärdera funktionen på ett bergvärmepumpsbaserat uppvärmningssystem för småhus med korta borrhål. För att kompensera för det korta borrhålet när en ny större och effektivare värmepump installeras har kollektorsystemet (dvs. borrhålssystemet) kompletterats med en solfångare kombinerad luftkonvektor, ”energikollektor”. Energikollektorns syfte är att tillföra energi till värmepumpens kalla sida, så att energiuttaget ur borrhålet inte ökar mot tidigare med den ersatta värmepumpen.

    Systemet har utrustats med flertalet energimätare samt en värmepumpsanalysator som samlar in och lagrar driftdata för systemet. Dessa driftdata visar för en dag i april, 2016, att energiuttaget ur kollektorsystemet via värmepumpen helt har kompensats av tillförd energi från energikollektorn. Dygnets medeltemperatur för detta dygn var 8.6 °C. Detta tyder på att syftet med systemet är uppfyllt och funktionen är den som initialt efterfrågades.

    Långtidsmätningar har inte gått att genomföra än, då installation av själva energisystemet, dvs. Värmestugan, försenats. Det intressantaste för en framtida studie är att se hur mycket energi, på årsbasis, som energikollektorn tillför kollektorsystemet, i förhållande till bortförd energi via värmepumpen. Det kunde noteras för undersökt dygn att temperaturen av vätskan in i värmepumpen signifikant ökade då energikollektorn tillförde energi. Kan detta även noteras sett över en årscykel? Solenergi som tillförs under varma tiden på året måste finnas kvar under uppvärmningssäsongen (dvs. ge en höge kollektorsystemtemperatur).

  • 25.
    Claesson, Joachim
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Boiling mechanism in a small compact brazed plate heat exchanger (CBE) determined by using thermochromic liquid crystals (TLC)1999Conference paper (Refereed)
  • 26.
    Claesson, Joachim
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Discrepancy between calculated and measured superheated area in an evaporator plate heat exchanger2002Conference paper (Refereed)
  • 27.
    Claesson, Joachim
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Performance of a compact brazed plate heat exchanger evaporator run in co-current and counter-current2003Conference paper (Other academic)
  • 28.
    Claesson, Joachim
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Pelletier, Olivier
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    On the influence of geometry on evaporation in compact brazed plate heat exchangers2001Conference paper (Other academic)
  • 29.
    Claesson, Joachim
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Rogstam, Jörgen
    Den fullskaliga testbutiken i miniatyr har öppnat2006In: Kyla+, no 8, p. 41-43Article in journal (Other academic)
  • 30.
    Claesson, Joachim
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Simanic, Branko
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Pressure drop and visualization of adiabatic R134a two-phase flow inside a chevron type plate heat exchanger2003Conference paper (Refereed)
  • 31.
    Claesson, Joachim
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Stare, Johan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Bergvärme kombinerat med uteluftkonvektor – Förbättrad SPF i stadsdelar med hög andel bergvärme2014In: KYLA+ Värmepumpar, ISSN 1100-343XArticle in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Att använda en uteluftkonvektor som kompletteringskälla är intressant för de installationer som finns i stadsdelar där avståndet till grannhål är kort. Genom återladdning kan ett nästan balanserat energiuttag ur berget erhållas och därmed nästan ett ”hållbart” energisystem. Projektet har visat att även om det (även för enskilda hål) ges mer gynnsamma förhållanden för konvektorn äts nyttan upp av de ökande driveffekterna för pump och fläkt. Noggrann analys behöver alltså göras innan dylikt system implementeras. För stadsdelar som Bromma kan det dock vara intressant för att dels undvika oväntade stopp av värmepumpen pga. för kalla brinetemperaturer, dels få ett balanserat energiuttag ur berget genom återladdning.

  • 32.
    Forsén, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Capacity control of a domestic heat pump: Part 2 System modelling and Simulation2002Conference paper (Refereed)
  • 33.
    Madani, Hatef
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Acuña, José
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    The Ground Source Heat Pump: A System Analysis With a Particular Focus on The U-Pipe Borehole Heat Exchanger2010In: 2010 14th International Heat Transfer Conference, Volume 4, 2010, p. 395-402Conference paper (Refereed)
    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.

  • 34.
    Madani, Hatef
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Ahmadi, Navid
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Experimental Analysis of a Variable Capacity Heat Pump System Focusing on the Compressor and Inverter Loss Behavior2010In: Proceeding International Refrigeration and Air Conditioning Conference, Academic Conferences Publishing, 2010Conference paper (Refereed)
    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.

  • 35.
    Madani, Hatef
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundquist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Capacity control in ground source heat pump systems part II: Comparative analysis between on/off controlled and variable capacity systems2011In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 34, no 8, p. 1934-1942Article in journal (Refereed)
    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.

  • 36.
    Madani, Hatef
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    A descriptive and comparative analysis of three common control techniques for an on/off controlled Ground Source Heat Pump (GSHP) system2013In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 65, p. 1-9Article in journal (Refereed)
    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.

  • 37.
    Madani, Hatef
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Retrofitting a variable capacity heat pump to a ventilation heat recovery system: modeling and performance analysis2010Conference paper (Other academic)
  • 38.
    Madani, Hatef
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Variable capacity heat pump systems, modeling and simulation2008In: 9th International Energy Agency Heat pump conference, 2008Conference paper (Refereed)
    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.

  • 39.
    Madani, Hatef
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    P5 – Dynamic heat pump system with capacity control2010Report (Other academic)
  • 40.
    Madani, Hatef
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Variable capacity heat pumps, modelling and simulation2008In: IEA Heat Pump conference Proceeding (2008) 9th International Energy Agency Heat Pump Conference, Academic Conferences Publishing, 2008Conference paper (Refereed)
  • 41.
    Madani, Hatef
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Wallin, Jörgen
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Ventilation heat recovery with run around coil: System analysis and a study on efficiency improvement – Part II2009Conference paper (Other academic)
    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.

  • 42.
    Madani Larijani, Hatef
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundquist, Per Gunnar
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Capacity control in ground source heat pump systems Part I: modeling and simulation2011In: International journal of refrigeration, ISSN 0140-7007, E-ISSN 1879-2081, Vol. 34, no 6, p. 1338-1347Article in journal (Refereed)
    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.

  • 43.
    Palm, Björn
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Effektiva plattvärmeväxlare som förångare i värmepumpar: Vidare studier. Slutrapport2005Report (Other academic)
  • 44.
    Palm, Björn E.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Plate heat exchangers, calculation methods for single- and two-phase flow2005In: ICMM 2005, Proceedings of the 3rd International Conference on Microchannels and Minichannels, Pt A, 2005, p. 103-113Conference paper (Refereed)
    Abstract [en]

    Plate heat exchangers were first developed about 100 years ago, but have won increasing interest during the last two decades, primarily because of the development of methods of manufacturing brazed plate heat exchangers. This type of heat exchanger offers very good heat transfer performance in single-phase flow as well as in evaporation and condensation. Part of the reason is the small hydraulic diameters, typically being less than 5 mm. Other advantages of plate heat exchangers are the extremely compact design and the efficient use of the construction material. In spite of their long use, the calculation methods for predicting heat transfer and pressure drop are not widely known. It is the purpose of this article to present such calculation methods for singe phase flow and for flow boiling and to discuss some of the specifics of this type of heat exchangers.

  • 45.
    Palm, Björn E.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Plate heat exchangers: Calculation methods for single-and two-phase flow2006In: Heat Transfer Engineering, ISSN 0145-7632, E-ISSN 1521-0537, Vol. 27, no 4, p. 88-98Article in journal (Refereed)
    Abstract [en]

    Plate heat exchangers were first developed about 100 years ago but have won increasing interest during the last two decades, primarily due to the development of methods of manufacturing brazed plate heat exchangers. This type of heat exchanger offers very good heat transfer performance in single-phase flow as well as in evaporation and condensation. Part of the reason is the small hydraulic diameters, typically being less than 5 mm. Other advantages of plate heat exchangers are the extremely compact design and the efficient use of the construction material. In spite of their long use, the calculation methods for predicting heat transfer and pressure drop are not widely known. It is the purpose of this article to present such calculation methods for single-phase flow and for flow boiling and to discuss some of the specifics of this type of heat exchangers.

  • 46.
    Stare, Johan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Sustainable Building Systems.
    Bergvärme kombinerat meduteluftkonvektor2014Report (Other academic)
    Abstract [sv]

    I detta arbete har problematiken kring befintliga bergvärmeanläggningar som varit i drift imånga år och är dags att byta ut undersökts. Fokus har varit på en specifik frågeställning, kandet finnas någon nytta med att komplettera befintlig värmekälla (bergkollektorn) med enuteluftkonvektor. Anledningen är de faktum att

    1. Nya värmepumpar är effektivare än gamla.

    2. Ny ”praxis” vid dimensionering gör att värmepumpar väljs relativt större än tidigare.

    3. I en del områden är det väldigt tätt mellan hålen, vilket gör att dessa kan påverkarvarandra.

    En effektivare värmepump använder, vid samma värmeavgivning till huset, mindre elektriskenergi, vilket betyder att större mängd energi tas upp ur hålet. Detta leder till försämradeförutsättningar för effektiv värmepumpsdrift och prestandan för värmepumpen kan blibetydligt sämre än förväntat.I detta arbete har ett stort antal variationer på en nyinstallerad värmepump undersökts för ett(av många möjliga) typiskt hus. Dels har det studerats hur en gammal byts mot ny, ny medkompletterande konvektor och ny med konvektor som även återladdar borrhålet. Även nyvärmepump med avbrottskriterier vid för kall brine samt borrhålsfält har studerats. Dessutomny värmepump dimensionerad enligt ”äldre” praxis, dvs 50 % effekttäckning vid DVUTistället för 70 %.Simuleringarna visar visserligen att konvektor i sig självt, och vid återladdning gervärmepumpen bättre driftsförutsättning, men inte tillräckligt för att kompensera för dedriveffekter som behövs för pump och fläkt som tillkommer vid dessa systemlösningar. Förborrhålsfält blir driftpunkten vid riktigt låga temperaturer, och i dessa fall kan värmepumpenvia styrsystemet stänga av kompressorn. I dessa fall visar sig konvektorn med återladdningsignifikant öka årsvärmefaktorn i förhållande till att inte installera den.Vidare visar simuleringarna att dimensionera den nya värmepumpen efter gammal praxis(50 % effekttäckning) tillsammans med luftkonvektorn och återladdning ger, trots ökatkyleffekt i värmepumpen, en driftpunkt som är jämförbar med den gamla. Det innebär attfinns det från början inga driftstörningar i form av avstängd värmepump har konvektorn medåterladdning den inverkan att problem inte kan förväntas med den nya effektivarevärmepumpen, trots det större momentana effektuttag en ny har.För alla andra fall kommer det nya systemet att betyda kallare energibrunn med risk förframtida driftsproblem.

  • 47.
    Wallin, Jörgen
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Bastien, Diane
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    The influence of energy conservation on the performance of solar thermal systems - A cold country case study2012In: 1st International Conference On Solar Heating And Cooling For Buildings And Industry (SHC 2012), Elsevier, 2012, p. 1069-1078Conference paper (Refereed)
    Abstract [en]

    The European Union has set a goal that the energy use in the built environment shall be reduced by 41 % to the year 2050 compared to 2005-2006. This could introduce new opportunities for solar thermal systems in cold countries. In such countries, like Sweden and Canada, the economy in solar thermal collector installation projects is often spoiled by the fact that most of heating energy demand of the building occurs during periods when the available solar energy is low. The present paper investigates the performance of solar thermal systems subjected to different quota between space heating and domestic hot water demand (DHW). This study investigates the performance of a solar thermal system integrated to four different buildings with varying heating loads in two different locations, Sweden and Canada. Models of single family houses are created which are able to simulate the total heating demand with different heating demand profiles but the same DHW demand. Simulations are performed in TRNSYS, an advanced tool used to simulate transient systems. Results indicate that solar combisystems tend to generate more useful energy and therefore be more cost effective when installed in buildings with higher heating demands.

  • 48.
    Wallin, Jörgen
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Analyzing the efficiency of a heat pump assisted drain water heat recovery system that uses a vertical inline heat exchanger2014In: Sustainable Energy Technologies and Assessments, ISSN 2213-1388, E-ISSN 2213-1396, Vol. 8, p. 109-119Article in journal (Refereed)
    Abstract [en]

    The purpose of the present study is to accumulate knowledge on how a drain water heat recovery system using a vertical inline heat exchanger and a heat pump performs under different drain water flow profile scenarios. Investigating how the intermittent behavior of the drain water influences the performance for this type of system is important because it gives insight on how the system will perform in a real life situation. The scenarios investigated are two 24. h drain water flow rate schedules and one shorter schedule representing a three minute shower.The results from the present paper add to the knowledge on how this type of heat recovery system performs in a setting similar to a multi-family building and how sizing influences the performance. The investigation shows that a heat recovery system of this type has the possibility to recover a large portion of the available heat if it has been sized to match the drain water profile. Sizing of the heat pump is important for the system performance; sizing of the storage tank is also important but not as critical.

  • 49.
    Wallin, Jörgen
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Improving heat recovery using retrofitted heat pump in air handling unit with energy wheel2014In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 62, no 2, p. 823-829Article in journal (Refereed)
    Abstract [en]

    The world is facing a challenge to reduce energy use to meet the environmental goals set for the future. One factor that has a great impact on the energy performance of buildings is the ventilation losses. To handle these losses, heat recovery systems with rotating heat exchanger are often implemented. These systems have been shown to recover about 60-70% of the energy in the exhaust air on an annual basis. After a heat recovery system is installed it is hard to improve the efficiency of the installed recovery system with an acceptable economic payback period. In the present paper one way to improve the energy performance of a building with this type of heat recovery system by the use of a heat pump is investigated by simulations in TrnSys. The heat pump system is arranged so that the evaporator is connected to a heat exchanger mounted in the exhaust airstream after the energy wheel, and the condenser of the heat pump is mounted so that the temperature of return water from the heating coil is increased. The simulations show that there is a possibility to increase the heat recovery rate of the air handling unit in a significant way by retrofitting a heat pump to the system.

  • 50.
    Wallin, Jörgen
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Claesson, Joachim
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Investigating the Efficiency of a Vertical Inline Drain Water Heat Recovery Heat Exchanger in a System Boosted with a Heat Pump2014In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 80, p. 7-16Article in journal (Refereed)
    Abstract [en]

    In the present study, the performance of a vertical inline drain water heat recovery heat exchanger is investigated. The system recovers the heat with the aid of a heat pump. To produce quality measurement data for the analysis special attention have been given to the calibration of sensors and the analysis of the propagation of uncertainty. The results from the analysis of the heat exchanger reveal that the contact resistance between the two copper pipes and the heat resistances on the inside of the drain water pipe are the dominating resistances to the heat transfer. Investigation of the heat recovery ratio shows that the heat exchanger has the capability to recover more than 25% of the available heat in the drain water at the flow rates investigated.

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