Simulation-Based Feasibility Study of Dry to Cool, a Desiccant-Enhanced Dew Point Cooling System for Air Conditioning Application in Indonesia
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Optimair, a Dutch-based company has successfully implemented their desiccant-enhanced dew point cooling, so-called Dry to Cool (D2C) system in typical European subtropical climate. Currently, Optimair is looking into the opportunity to deploy the D2C system in Indonesia where its hot and humid climate typically challenges the performance of conventional evaporative cooling. This study aims to investigate the influence of technical factors from the building envelope to the solar thermal system parameters on the D2C system performance by means of simulations in TRNSYS environment and sensitivity analysis.
Considering a reference office building site in Jakarta, which has 20% of window-to-wall ratio with infiltration rate of 0.035 ACH is scheduled to run with effective working hours of 2871 hours/year, the proposed D2C system with dehumidifier set point at 0.0103 kg/kg could provide monthly indoor temperature between 24.8oC-27.3oC while maintaining 60% relative humidity throughout the year. In view of the regulations in Indonesia which recommends criteria of 24oC-27oC with relative humidity between 55% and 65%, this result is satisfactory.
The solar-driven D2C with 150.15 m2 of solar collector area and 9 m3 of 3 m height hot water buffer tank has annual cooling capacity of 804.67 MWh/year with peak cooling load of 388.7 kW. This system has annual DCOPnet (ratio of the cooling capacity to the total of regeneration energy from any heat source and the regeneration fan power consumptions) of 3.28 and SCOP (ratio of the total cooling capacity to the power input including the back-up heater with electric-to-thermal coefficient of 1, the regeneration fan and the pump power) of 7.32. In the case that the considered heat pump with COP of 3 solely provides the required thermal energy, SCOP of 8.5 can be gained. Furthermore, SCOP of 36.5 could be attained when the regeneration energy is obtained readily from free waste heat.
Compared to a conventional water-cooled chiller with COP of 3.2, potential annual energy savings of 56.3% could be achieved with the proposed solar-driven D2C system. This could be improved up to 80.4% by using 23% more efficient regeneration fan and back-up heat source with electric-to-thermal coefficient of 0.33. When the D2C is solely driven by the heat pump, an annual energy saving of 62.4% is expected. The utilization of free waste heat would save 91.2% of annual energy consumption. These cases translate to yearly operational economic savings between 14,300 and 23,000 EUR.
Place, publisher, year, edition, pages
2014. , 65 p.
IdentifiersURN: urn:nbn:se:kth:diva-149940OAI: oai:DiVA.org:kth-149940DiVA: diva2:741574
2014-08-26, M263, Brinellvägen 68, 11:00 (English)