ENERGY EFFICIENT BUILDING DESIGN AND THERMAL ENERGY STORAGE

Abstract

This chapter discusses the potential for cost-effectively reducing the energy intensity of office buildings by applying proven technologies, especially the use of ground source systems with thermal energy storage. It is shown that significant energy use reductions are possible without increases in capital costs and that reductions of more than 50% are possible within normal investment criteria. Energy storage techniques need to be adapted to these reduced energy levels. Energy efficient buildings are better suited to energy storage. Low-energy building design can contribute to dramatically reduced energy usage and can be applied to all new building projects. The example of a small office building located in Canada is used to illustrate this potential. The reference energy level is that specified by the minimum (or prescriptive) requirements of the Canadian Model National Energy Code for Buildings (MNECB) 1997. Costs and savings evaluated include energy, capital and maintenance. Typical small and large office buildings were analyzed. The role of energy storage was also considered. The results indicate that energy savings greater than a 50% reduction can be achieved with attractive economic returns through careful selection and application of existing technologies. Energy savings greater than 50% were achieved in four cases for the small office building with discounted payback periods between 2.5 and 6 years. The 50% energy reduction relative to the MNECB is the threshold for high performance buildings. It is possible to achieve 25% reduction compared to the base case building with no incremental cost. With careful selection and application of efficient building technologies at the early stages of design, and adjustment of equipment sizing to account for reduced demands, many designs result in energy savings of 30-40% with no incremental cost. A brief guide to design options for the building side of ground source heat pump systems is then presented. Ground source heat pump systems can significantly lower heating and cooling operating costs and can qualify designs for energy efficiency and renewable energy credits under various building rating schemes. Both distributed or incremental heat pumps and central heat pumps as applied to closed loop ground source systems are considered. Available products are identified for each design option as well as pumping arrangements, system