In-situ assessment of a solar vacuum tube collectors installation dedicated to hot water production

Abstract

In order to improve the contribution of solar thermal energy in moderately insolated regions, solar installations have to be optimized and their heating capacity has to be proven. In this aim, an in-situ thermal performance investigation was carried out on a solar installation of 24 “Water-in-Glass” evacuated tube collectors coupled to their storage unit in a northwest European climate. The aim of the installation is to provide a calf-breeding farm with an intermittent supply of water at 80 °C. The particularity of this solar installation is the specific arrangement of this kind of solar water heater in series and in parallel. Instrumentation was implemented to understand and establish energy balances. An analysis was carried out on four sequences representative of each season. The results show that despite mostly unfavorable sky conditions, the solar installation was capable of providing from 12 to 67% of energy needs for these four sequences.

Keywords

• Intermittent solar water heating
• Specific arrangement of solar collectors
• Water-in-Glass evacuated tubes
• In-situ experiment
• Operative thermal efficiency
• Assessment of thermal performance