Sizing of a Solar Water Heater – Heat Pump Water Heater Hybrid Design; Case Study of Comfort Gardens Hotel

Abstract

Project title: Sizing of a Solar Water Heater – Heat Pump Water Heater Hybrid Design; Case Study of Comfort Gardens Hotel. Author: Japheth Kiptoo Sang - F56/11914/2018 Heating requirements in particular, water heating in hotels constitutes approximately 28% of the total energy costs, which translates to higher emission levels to the environment. These high costs of energy have necessitated the use of energy and environmental management systems to curb the energy costs. Hoteliers have adopted the use of emerging and popular technologies mostly renewable energy technologies. They include the use of solar water heaters, heat pump water heaters, and efficient boiler among others. This research focuses on the viability of using a combined SWH and a HPWH in a hybrid setup for a hotel. Comfort Gardens hotel was used as the case study for this research, providing the data required for design. A hybrid water heating system was sized, designed and was guided by the use of software RET screen, Polysun and SAM. The designer selected two HPWH with a heating capacity of 90 KW each to compliment the 17 solar panels sized to meet the demand of 118.47 Kwh/day. The total demand to be supplied by the HPWH is 78.98 Kwh/Day with one HPWH acting as a backup. An economic analysis done found the NPV and IRR for scenarios A and B were estimated to be Kshs 5,121,699 ($ 44,536), Kshs 6,599,700 ($ 57,389) for the NPV and 33.06%, 39.63% for the IRR respectively. Payback periods for Scenarios A and B computed gave an estimated 2.85 and 2.43 years respectively. From all the financial evaluations, a positive NPV for both scenarios confirm the viability of the project while the payback of approximately 2 years for both scenarios was realized. Recommendations on areas of further studies are proposed in the report. Keywords: Solar Water Heaters (SWH), Heat Pump Water Heaters (HPWH), Payback Period, Net Present Value (NPV), Internal Rate of Return (IRR).