Theoretical study of solar combisystems based on bikini tanks and tank‐in‐tank stores

Abstract

Purpose -Low flow bikini solar combisystems and high flow tank-in-tank solar combisystems have been studied theoretically. The aim of this paper is to study which of these two solar combisystem designs is suitable for different houses. The thermal performance of solar combisystems based on the two different heat storage types is compared. Design/methodology/approach -The thermal performance of Low flow bikini solar combisystems and high flow tank-in-tank solar combisystems is calculated with the simulation program TRNSYS. Two different TRNSYS models based on measurements were developed and used. Findings -Based on the calculations it is concluded that low flow solar combisystems based on bikini tanks are promising for low energy buildings, while solar combisystems based on tank-in-tank stores are attractive for the houses with medium heating demand and old houses with high heating demand. Originality/value -Many different Solar Combisystem designs have been commercialized over the years. In the IEA-SHC Task 26, twenty one solar combisystems have been described and analyzed. Maybe the mantle tank approach also for solar combisystems can be used with advantage? This might be possible if the solar heating system is based on a so-called bikini tank. Therefore, the new developed solar combisystems based on bikini tanks is compared to the tank-in-tank solar combisystems to elucidate which one is suitable for three different houses with low energy heating demand, medium and high heating demand.

Solar Water Heaters: A Review of Systems Research and Design Innovation

“…The domestic hot water is withdrawn directly from the tank. Theoretical investigations of bikini solar combisystems [3] have shown that bikini systems are suitable for low-energy buildings because they operate most effectively at the low auxiliary volume set point temperatures that then prevail [24].…”