Sensitivity Analysis of Two Solar Combisystems Using Newly Developed Hot Water Draw Profiles

Abstract

This research addresses the viability of two solar combisystems, which use solar energy to provide both space heating and domestic hot water, for several single family homes in Ontario.Hot water use data from seventy three homes were refined to create twelve different draw profiles representing a variety of consumers. These profiles were divided up based on the magnitude of daily draw and the preferred time of use. It was determined that time of use had little to no effect on performance. However, the magnitude of a daily draw was seen to have a significant effect on the final energy use of a home.Two different combisystem plant configurations, a single tank system and a two tank system, were simulated. It was determined that the single tank system offered superior performance. Unless systems were sized to the upper limits tested here, a solar fraction of 50% could not be achieved.iii Dedicated to my parents. Your love and support know no bounds.iv

Seasonal Thermal Energy Storage in Buried Water Tanks for Single Detached Houses

“…The most common (albeit, imperfect) performance metric for solar thermal systems is the solar fraction, f : f = Energy supplied by solar heat Total energy demand (1.1) Solar combisystems equipped with only diurnal heat storage can only achieve overall solar fractions of about 50-60% (Dincer and Rosen, 2011). Edwards (2014) examined the viability of combisystems with short term heat storage (up to 2000 L) for Canadian housing stock. Results showed that the combisystems were not able to achieve the target solar fraction of 50%.…”

Analysis and Design of a Solar-Combisystem for High Solar Fraction Canadian Housing with Diurnal and Seasonal Water-Based Thermal Stores

“…The increasing demand for solar based heating systems and the cost-eectiveness of combisystems led the IEA to convene the Solar Heating and Cooling Programme (Task 26) to study the complex interactions between the system components to improve overall performance (International Energy Agency, 2014). Likely one of the largest international eorts to develop the combisystem eld, the Task ran from 1998 to 2002 and led to the publication of the Solar Heating Systems for Houses: A Design Handbook for Solar Combisystems (Edwards, 2014;Weiss, 2003). Dierent system designs were investigated using annual TRNSYS simulations for climate conditions of northern, central, and southern Europe locations (International Energy Agency, 2003).…”

“…Further foundational work in the area of solar combisystems and domestic hot water (DHW) draw proles was conducted by Edwards (2014). DHW draws can vary widely in terms of time-of-use and overall consumption which may aect simulation conclusions.…”

“…DHW draws can vary widely in terms of time-of-use and overall consumption which may aect simulation conclusions. Edwards (2014) showed that the overall magnitude of the draw prole had the greatest impact on overall energy use. The DHW draw proles collected from measured data were utilised in this work and will be elaborated on in Chapter 2 (Edwards et al, 2015).…”

“…• to horizontal to charge the thermal stores (refer to Figure 19). Evacuated tube collectors were chosen based on earlier recommendations by Edwards (2014) and research by Wills (2013). The higher collector temperatures achieved with evacuated tubes were also desired for potential future experimental work with an absorption chiller for solar-assisted cooling research.…”