The backbone of EVBF’s operations are its geothermal and solar thermal heating and hot water systems. These technologies produce clean renewable energy to meet the housing projects’ needs. EVBF’s strategy optimises the performance of its renewable energy infrastructure by complementing it with high efficiency natural gas boilers to meet peak demands.
1. Geothermal space heating
Space heating and cooling are achieved by ground-source heat pumps connected to sixteen 200m-deep wells. Ground source heat pumps take advantage of the fact that the temperature underground remains constant throughout winter and summer. In the winter, heat from the ground is collected to heat the buildings. In the summer, the excess heat from the buildings can be transferred back to the ground to cool the buildings’ interiors.
2. Solar power for hot water
Some 225 m2 of evacuated solar collectors, located on the roof of Chez Soi and Z.O.O., provide domestic hot water and send excess heat in the summer back to the ground through the heat pumps. Additional hot water reservoirs store enough solar heated water to meet an entire days needs, which maximises the benefits of the solar collectors and helps to ensure that ample hot water is available at all times.
3. Solar Wall
A south-facing solar wall preheats make-up air for Chez-Soi’s ventilation system. During the winter, incoming air is passed over a 48 m2 solar wall surface before entering the building. This allows Chez Soi to maintain a high rate of air exchange in the building and achieve high interior air quality, while reducing the costs of pre-heating make-up air.
4. High-Efficiency Natural Gas Back-up Boilers
Additional heating and hot water needs are met through high-efficiency natural gas boilers (with over 90% efficiency ratings) located in each of the buildings. This hybrid system has been optimised to ensure high energy efficiency, reliability and affordability.
By integrating gas boilers with the renewable energy technologies, EVBF’s heating strategy derives the maximum benefit from the solar and geothermal systems, using them to their full capacity for the greatest portion of the year. For the shorter period when peak demands occur, or when the temperature drops very low, the natural gas boilers give the system the extra capacity it needs.
This integrated strategy is expected to provide heating at a cost as low as half that of what would be the cost if gas boilers were used alone, while maintaining the same responsiveness and reliability. Moreover, the gas boilers can be used to meet all the buildings’ heating and hot water if the solar or geothermal systems are not available.
