Sustainable Energy in Building Systems

Abstract Sustainable energy in buildings refers to efforts to reduce or eliminate the need to burn fossil fuels for space heating and cooling. In the USA buildings use one-third of our total energy, two thirds of electrical energy and one eighth of water. U. S. Green Building Council (USGBC), that promotes sustainability in how buildings are designed, built, and operated has designed or introduced a Leadership in Energy and Environmental Design (LEED) green building rating system.*(1) It has been helping professionals across the country to improve the quality of buildings and their impact on the environment. More and more building professionals, owners and operators are seeing the benefit of green buildings and LEED certification. Green design reduces the operating costs, enhances building and organizational marketability, and increases occupant productivity. In existing buildings, energy sustainability can be accomplished through increased efficient energy use, in conjunction with decreased energy consumption and/or reduced consumption of conventional energy sources. In these buildings, fossil fuels are burned on-site as primary energy and off-site to generate electricity for secondary energy. Heating is most often needed in an occupied space in the seasonal cold climate regions of the world. Higher energy consumption and costs involved with meeting this need motivates us to find ways to improve the efficiency of the existing processes. Convective heating is the most popular type of heating which heats the space by blowing air to transfer heat across the heating coil. As most of the manufacturing facilities are built to have higher ceilings to accommodate all the equipment, the convective space heating process is energy inefficient for the needed ambient temperature. Also, as it is air that is heated up during the convective heating process and it tends to leak across the shell of the building losing the energy, especially in the manufacturing plants, most of which are housed in very old buildings. In addition, using the convective heating tends to heat up whole air to maintain the given space at certain needed temperatures. Also most of the convective heaters are capable of achieving a maximum of 85% efficiency. The actual efficiencies might be a bit lower than that. The students and the staff of the Bradley University Industrial Assessment Center (BU IAC) have assessed about 425 manufacturing plants in the states of Illinois, Indiana, and Missouri since 1993. A majority of these plants were housed in very old buildings with envelopes in very poor repair. Many buildings were found to have no insulation and with several openings. This was resulting in high space heating costs and thermal discomfort for the occupants. The purpose of the work reported in this paper was to explore the feasibility of radiant space heating as a sustainable energy for space heating in manufacturing plants. Several case studies based upon the work done by the staff and students of the BU IAC are presented in this paper. BU IAC is a U. S. Department of Energy (DOE) sponsored program with the objective of implementing energy efficiency and cost savings for small and medium sized manufacturing plants while educating tomorrow's energy engineers. Currently there are 24 such centers in the country and Bradley University has one of them since 1993. Success stories of the DOE's IAC program are discussed in the paper.