Introduction

Solar thermal systems are commonly used for the domestic water heating, space heating, (industrial) process heating, and even for cooling of goods and buildings. The Energy Independence and Security Act (EISA) 2007 SEC. 523 requires that “if lifecycle cost-effective, as compared to other reasonably available technologies, not less than 30% of the hot water demand for each new Federal building or Federal building undergoing a major renovation be met through the installation and use of solar hot water heaters.” In the United States, different types of solar water heating systems are available and primarily used for standalone buildings. Different design guidelines are available from the National Renewable Energy Laboratory (NREL) and American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) for small size systems. These systems are relatively complex and application of solar based heating in the United States is often limited by economical considerations when compared to traditional heating systems and local cost of fossil fuels.

In recent years, numerous innovations in solar thermal technologies have resulted in cost effective large scale systems including integrated solar supported heating networks. Examples of such systems installed in Denmark, Germany, Austria and other countries have proven that such systems are reliable and may be more economical compared to small scale systems. Such systems may be cost effective for clusters of buildings containing e.g., Army barracks, dining facilities, gyms, child development centers and swimming pools. Similar opportunities exist on large hospital campuses, family housing complexes, etc.

This course will assist an engineer with recommendations on optimal and reliable configurations of solar water heating systems in different climates along with design specifications, planning principles, and guidelines for such systems that serve building clusters with significant domestic hot water (DHW) needs (e.g., homes, dining facilities, Child Development Center [CDC], Gyms) that operate in combination with central heating systems. Note that, throughout the industry, the terms “district heating system” and “central heating system” are commonly used interchangeably. For the purposes of this course, the term “Central Solar Hot Water System” is used to denote systems that serve clusters of buildings from a large centralized solar thermal field(s) (in contrast with small size solar thermal systems that serve standalone buildings). The guidelines are complemented by numerous case studies of successfully implemented solar supported thermal networks along with results of exemplary simulations of different system options based on real world scenarios. This course also discusses the benefits and disadvantages of large scale centralized versus decentralized solar thermal systems.