Modeling of a solar water heating system for a private hospital in Sana’a, Yemen using TRNSYS: دراسة استخدام الطاقة الشمسية لإنتاج المياه الساخنة لمستشفى خاص في صنعاء باستخدام برنامج المحاكاة TRNSYS

The objective of the present work is to simulate and analysis the performance of a proposed solar water heating system for a 160-bed capacity private hospital in Sana’a City-Yemen. The systems consist of solar collectors, hot water circulation pump, a storage tank with an electrical heater, and identical auxiliary components. The simulation and the thermal performance analysis have been done using TRNSYS software. In addition, a comparison between the performance of evacuated tubes collectors and flat plate collectors was done to justify the selection of ETC for the designed. The thermal performance analysis shows that the evacuated tubes collectors have an annual contribution of 87.73 MWh with an annual average solar fraction of 63 percent and annual average installation efficiency of 68 percent.

Decoupling the Monitoring of Solar Water Heaters and their Usage Profiles

South Africa is the most technologically advanced nation in Africa. However, the country is plagued with constant load shedding. The country receives about 2500 sunshine hours annually, with daily average irradiation levels of 4.5–6.5 kWh/m2. Despite these potentials, the use of electricity for domestic water heating is still prevalent in the country. The mass rollout of solar water heating (SWH) technologies in the low-cost housing sector across the country were met with massive failures. This study aims to assess the energy yield of a passive flat plate and an evacuated tube solar water heating system by evaluating the performance of these systems to address the energy crisis in South Africa. The flat plate (FP) and evacuated tube (ET) solar water heating systems were monitored for four days, characterised by varying sky conditions through instantaneous data measurement at 5 s. The parameters measured were water temperature, ambient temperature, irradiance at the plane of array, relative humidity, wind speed and direction. The results obtained show that a maximum irradiance of 1050 W/m2 was obtained on a clear day and corresponded to a hot water temperature of about 58 °C and 65 °C for the FP and ET, respectively. However, a cloudy day with a maximum irradiance of 400 W/m2 produced about 22 °C and 29 °C of hot water for the FP and ET, respectively. The results obtained in this study will guide stakeholders in the renewable energy sector towards employing SWH systems to replace or augment the electric geyser. Solar water heaters (SWH) can be used in the low-cost housing sector to provide hot water. Hence, the assessments in this study offer essential information for the deployment of these systems to reduce demand on the ailing South African electricity utility, Eskom, and mitigate climate change.