Prototype Development and First Test Results of a Facade-Integrated Solar Thermal System for Domestic Hot Water Preparation
Abstract
Solar thermal systems with roof-mounted collectors and basement-located heat stores represent a mature technology for solar space heating and domestic hot water preparation in residential buildings. However, due to the limited available roof area, an increase of the solar fraction is often not possible. Especially in case of multi-story residential buildings with a low ratio of roof area to living area and dwelling units, the façade- integration of solar thermal components seems to be the only solution for covering considerable parts of the heat demand (> 50 %) by solar energy. Placing solar collectors in front of the façade is the most common technique when conducting building- integrated solar thermal (BIST), but actually more ambitious approaches in this field are needed for achieving a real architectural and technical integration. So-called multifunctional solar thermal façade components combine the features of a standard building façade such as thermal and noise insulation and protection against environmental influences with the functions of a solar thermal system, i.e. generation, storage and distribution of solar heat. In this paper the development and construction of a prototype of such a multifunctional solar thermal façade element is presented. The façade element comprises a complete solar thermal system for the preparation of domestic hot water and it consists of a transparent thermal insulation as energy-harvesting component, a hot water tank as absorber and heat store, different types of thermal insulation and the entire hydraulic circuitry (except for the controller) for the supply of the hot water to the dwelling unit. Besides the description of the technical details and characteristics of the different components, this paper will focus on different options for the integration of the multifunctional solar thermal façade element into the building envelope. Furthermore, approaches for envisaged laboratory and outdoor testing will be presented in this paper.
Keywords
Building-integrated solar thermal (bist), Multifunctional façade element, Solar thermal system