Healthcare facilities need to meet a set of standard ventilation requirements and air change per hour rates – typically higher than those found in most other buildings – and their large heating, ventilation, air conditioning (HVAC) and water heating systems consume a substantial amount of energy. This conditioning is commonly referred to in the industry as “reheat” and is accomplished from the on-site combustion of natural gas. Research uncovered that one of the biggest end-uses of energy within hospitals is re-heat, which can account for 42 percent of a hospital’s energy consumption. Given that there have been no new developments of technologies of ventilation reheat, beyond improved boiler efficiencies, the most common proposal to reduce reheat energy in healthcare is to reduce ventilation. Reducing ventilation increases the risk of airborne infections in these facilities. Accepted and enforced code ventilation requirements have not been reduced due to a lack of research and evidence supporting the theory that reducing ventilation in healthcare is safe. This paper aims to identify the potential for industrial-scale solar thermal (ST) systems for the integration into a hospital’s ventilation reheat systems. It describes the design, performance, and economics of a solar thermal-assisted heating application into a hospital’s ventilation reheat system in California, offsetting the use of common petroleum-burning boilers to produce the hydronic heating for ventilation reheat in a hospital. The use of solar thermal energy would provide a key opportunity to decrease the reliance on fossil fuels and associated risk of price volatility, while greatly reducing carbon emissions from the site. This would improve air quality around a hospital to the benefit of staff, patients and neighbors all while continuing to ensure the aseptic quality of the air inside the facility.




Dr. Monika Weiss, Co-founder of ergSol, is driven by her strong belief in sustainability, her passion for innovation, and her focus on best fit solutions all to shape a place worth living for generations to come. ergSol provides innovative, advanced solar thermal heating and cooling solutions. Emphasis is placed on integrated solutions designed to fit the customer needs and to ensure installation efficiency and easy maintenance.

Monika is an environmental pioneer and management consultant with extensive national and international experience in helping people and organizations turn potential to success. She has a strong background in collaborative leadership in cross-cultural, multi-industry environments and public-private consortium. As an experienced project manager and change agent she is committed to developing sustainable organizations. Her skills include finding organizational forms to fit the tasks of innovating a new technology; preparing the infrastructure and raising the public awareness for product commercialization; valuing diversity to create synergy. Monika’s work focus is on sustainable business strategies and renewable technologies, especially in the solar thermal realm. She holds a M.S. in Mathematics and a Ph.D. in Organizational Psychology.