Abstract
One of the biggest obstacles to economic profitability of solar water heating systems is the investment cost. Retrofitting existing domestic hot water heaters when a new solar hot water system is installed can reduce both the installation and material costs. In this study, retrofitting existing water heaters for solar water heating systems in Swedish single-family houses was theoretically investigated using the TRNSYS software. Four simulation models using forced circulation flow with different system configurations and control strategies were simulated and analysed in the study. A comparison with a standard solar thermal system was also presented based on the annual solar fraction. The simulation results indicate that the retrofitting configuration achieving the highest annual performance consists of a system where the existing tank is used as storage for the solar heat and a smaller tank with a heater is added in series to make sure that the required outlet temperature can be met. An external heat exchanger is used between the collector circuit and the existing tank. For this retrofitted system an annual solar fraction of 50.5% was achieved. A conventional solar thermal system using a standard solar tank achieves a comparable performance for the same total storage volume, collector area and reference conditions.
Highlights
One of the biggest obstacles to the economic profitability of domestic solar water heating (SWH)systems is the investment cost [1,2,3]
The collector area was set to m2 since it represents a balance between a high annual solar fraction and collector area
Different collector areas would impact the absolute value of the annual solar fraction but not the relative performances between the systems
Summary
One of the biggest obstacles to the economic profitability of domestic solar water heating (SWH)systems is the investment cost [1,2,3]. The installation cost of forced circulation systems used in cold climates can represent up to 50% of the total investment cost depending on the size and type of system [4]. Retrofitting existing domestic water heaters when new SWH systems are installed can reduce the total investment cost by decreasing both the installation and material costs. In Sweden there are more than half a million electrically heated single family houses that use conventional water heaters for domestic hot water production [5]. Such retrofitting needs to be carried out with consideration of the cold Swedish climate. There are two main types of systems designed with an external heat exchanger outside the storage: thermosyphon and forced flow circulation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
