Tomas Matuska, Czech Technical University in Prague

Borivoj Sourek, Czech Technical University in Prague, ENKI Trebon

Rational use of energy in buildings leads to a concept of active energy facade like transparently insulated massive walls, solar thermal or PV facades, advanced glazings for daylighting purposes or double ventilated facades. The paper is concerned on facade-integrated solar thermal collector concept for water heating in existing building stock in Czech Republic (panel and brick block of flats), which is to come through complex renovation (thermal insulation, windows, heating systems). Thermal behaviour of facade collector compared to standard roof-located collectors has been investigated.

Introduction

Large amount of flats (cca 2.3 millions) is concentrated in housing estates (panel or brick block of flats) in Czech Republic. The housing estates established between 50’s and 70’s should pass through complex renovation. Energy-conscious retrofit takes into account the reduction of building heat losses (thermal insulation, windows, mechanical ventilation with heat recovery), systems of control and measurement, devices for hot water consumption reduction or reconstruction of heating systems (distributed plants) and renewable energy sources exploitation. Solar energy utilization has a large potential for water heating (domestic hot water — DHW) in these buildings. However, there are often problems to locate collector field on the flat building roofs (lift housing, ventilation facility etc) or such roof-located system is rejected by architects (collector field on the flat roof is not an integral part of building). Facade collector concept could help to overcome these technical and aesthetical barriers and to bring another advantages. Today, the concept is tested in first pilot installations in Czech Republic. Technical support in the form of computer simulations is needed to bring the possible problems and risks into light and to suggest efficient solutions for individual applications.