Type or paste a DOI name into the text box. Therefore, HVAC is a key component of climate change mitigation potential in the building sector. HVAC systems normally consist of components to supply, filter, heat, natural ventilation in buildings a design handbook pdf and distribute the conditioned air into targeted interior spaces. This means the high-efficiency of one component can operate at expense of the others.
As an example, take two categories of HVAC systems: high- and low-pressure systems. As highlighted, highly efficient HVAC systems can be achieved through the best-fit integration of HVAC’s key components. These key components, or sub-systems, are heating, cooling and ventilation. These components have constantly undergone technological upgrades to improve their efficiency. Boilers are usually used to generate hot water or steam using coal, diesel or natural gas.
Heat pump technologies are developed as an alternative to fossil-fuel-based boilers. The technologies extract heat from warmer underground earth, air or sub-surface water during winter months, in temperate regions, to condition the temperature for indoor usage. Reversing the above cycle during summer months, a heat pump extracts heat from indoors to outdoors to provide cooler indoor temperature. Chillers are used to produce cool water, which is then pumped to air handling units to cool the air. Chillers use either mechanical compression or an absorption process. Among mechanical compression chillers, centrifugal chillers are the most efficient for large-capacity operation, such as in large office buildings or retail complexes. Absorption chillers, on the other hand, produce cool water through heat sources, i.
Condensers are required in chiller systems, which reject heat to the environment and allow chillers to continuously remove heat from indoor conditioned spaces. They can be air-cooled or water-cooled. Aircooled condensers are used for small-scale application, whereas water-cooled condensers are more costly but much more efficient for large-scale systems and are usually seen in large building complexes. Diagram of a typical conventional cooling and ventilation system. Energy recovery installed in the mechanical ventilation system can help save energy. Air conditioned air fume cupboards can be use to cool incoming replaced air through a heat exchanger instead of being discharged directly outdoors. An automatic condenser tube cleaning system allows water-cooled heat exchange type chillers to maintain good performance through constant cleaning of the condenser tubes.
Diagram of a typical energy efficiency cooling and ventilation system. Displacement ventilation typically supplies conditioned air from a raised floor system through a series of adjustable floor-mounted registers. HVAC systems and their sub-systems more feasible for large-scale implementation, especially in the context of developing countries. One of the major barriers to implementing highly efficient HVAC systems is the installation of oversized systems that result in inefficient part-load most of the time.