Water Source Heat Pumps Sytem Principles

The decentralised approach
Nearly all central HVAC systems have poor part-load efficiencies. At design load conditions, the best central systems operate magnificently, but during most of the annual operating hours, they consume a disproportionate amount of energy, maintaining a holding pattern, contributing very little energy to actual building heating or cooling. The desirability of having heating or cooling available in any room, at any time, is obvious, but most central systems fill this need with “energy bucking” approaches, which divide the air conditioning medium (air or water) in two; part is overheated and part is overcooled. The medium is delivered to the space, mixing the hot and cold quantities as required to maintain the desired space temperatures. A terminal unit in each zone or room provides inherent energy conservation. Each unit heats or cools as required, whenever desired, only to the extent necessary, thus allowing the realisation of diversity in heating, cooling and electrical use. The second major step is to make the terminal units water source heat pumps, and interconnect them with a closed water loop. This allows transfer of energy from satisfied spaces in the building to areas lacking sufficient energy. The closed water loop permits efficient energy transfer (there is probably no less efficient method of transferring energy over long distances than using air as a heat transfer medium).