8 - Active solar space heating

Abstract

This chapter presents the background for active solar space heating development and recent efforts to reduce energy consumption for space heating in buildings. Changes in space heating concepts and the technology applied are described. The development of solar combi systems, for domestic hot water and space heating, and their modes of operation are discussed. Various methods of classification of the systems are considered. Examples of various configurations are shown and analyzed. The main components of the systems are described. Focus is placed on the heat storage elements. The energy balance of the storage tank is mathematically described and solved. Some results of calculations of water temperature fluctuations in a storage tank are presented. The role of heat stratification in a tank for increased energy performance of a heating system is described. Applications of phase-change materials in storage tanks and in building materials are presented. Various modes of operation, configurations, and functions of the systems are analyzed. The idea of solar hybrid systems operating based on subsystems using different energy sources is described. Benefits of coupling solar energy systems with heat pumps are described. The schematics of various configurations of a solar system with a heat pump are presented. The focus is on solar heating systems coupled with ground heat pumps. Possible applications of active solar space heating systems on small, medium, and large scales are analyzed. Conditions influencing the energy efficiency of the systems are discussed. Some results of calculations of the share of solar energy supplied by various solar systems are presented. It is shown that the solar energy fraction does not express the total efficiency of the system. Therefore the seasonal performance factor is proposed to be used to evaluate the performance of the systems. Future improvements of the systems are presented, mainly as building-integrated solar thermal systems.