Making comfort and energy efficiency go hand in hand
While the erratic progress of the new Part L of the Building Regulations, which is not now expected to arrive until April 2006, may delay the legislative framework for reducing the energy consumption of buildings, this issue is one that should always concern building-services engineers. That, indeed, is the topic of the main feature in this issue of Modern Building Services. One of the threads running through this feature is that using energy-efficient equipment does not necessarily lead to an energy-efficient system. Indeed, building services that deliver greater comfort can often be associated with higher levels of energy efficiency. And thirdly, delivering comfort in a different way can require the use of less energy. It is evident that the best solutions will be achieved using the imaginative and skilful use of engineering principles. What engineer will not share Graham Williamson’s enthusiasm for seasonal efficiency as a measure for conforming to Building Regulations (page 18)? As a director with Ideal Boilers, Graham Williamson’s interest is with boilers and heating systems. One aspect of system efficiency he highlights is that a correctly size standard-efficiency boiler can offer similar savings to an equivalent condensing model in a system that cannot permit condensation. Worthy of note, too, is Guy Kennett’s explanation of the benefits of variable-speed drives (page 20). Used with fans and pumps, variable-speed drives could, perhaps, halve the energy consumption of such equipment. Very impressive, but Guy Kennett sees reduced energy consumption almost as secondary to the potential for improving the environment in buildings. On the air-conditioning front, higher temperatures and energy efficiency must go hand in hand. In achieving this, Andrew Keogh (page 15) questions the design temperatures that are generally accepted. Rather than design for peak temperatures that are seldom reache, he suggests designing for lower temperatures so that plant and systems are smaller and run closer to their optimum efficiency for a higher proportion of the year. The consequence, a relatively minor consequence, is that on very hot days the temperature in buildings will drift a little higher than, say, 22°C. An effective approach to cooling buildings that caught our imagination is the pooling of Passivent’s expertise in natural ventilation with Mitsubishi Electric’s air-conditioning knowledge (page 24). A system approach to combining air conditioning and natural ventilation has been developed and trialled by these two companies — and found in a real project to reduce energy consumption by 41% compared with mechanical cooling and powered ventilation. What is abundantly clear is that given the opportunity and freedom to express themselves, engineers can deliver building-services systems that are more effective at delivering comfort and more efficient in their use of energy than when they are hidebound by prescriptive approaches.