air conditioning

Over the last 15 years, active desiccant systems have become a common component of HVAC systems in commercial buildings needing lower-than-usual humidity levels. Ice arenas, supermarkets and refrigerated warehouses all contain refrigeration systems which cool air more effectively when most of the building's moisture load is removed by an active (heat-reactivated) desiccant system.

BSRIA are currently conducting a research project aimed at promoting identification and amelioration of plant oversizing, with particular emphasis on providing assessment of potential energy savings achievable through the application of remedial measures. The objective of the project is to update existing BSRIA guidance, which will provide building operators with information on how to identify excess HV AC plant capacity and how to enhance the performance of such plant.

Suitable combinations of desiccant and evaporative cooling systems permit air processes alternative to the traditional ones for air conditioning applications. But owing to the high costs of desiccant wheels, we need very strong energy savings in order to demonstrate an economy validity. These savings can be possible today by the last generation of desiccant wheels where the most part of the regeneration heat can be supplied by heat recovery from chillers.

The HVAC components are usually made of galvanised sheet metal which is covered by a corrosion protection and also lubricant oils are used in machine tools in manufacturing of the components or ducts. The aim of this study was to test and develop a consistent method to determine oil concentrations on component surfaces. Two swiping methods and a filter contact method were tested. In al of them the analysis based on IR-spectrometry. The results show that oil concentration is quite high and unequally distributed on the surface of the sheet metal containing corrosion protection oil.

This technical note considers the performance evaluation of an advanced air-conditioningsystem in a plant manufacturing electrical generators. The extensive field measurements ofthermal climate and indoor air quality were performed during five periods of extreme weatherconditions in 1994-1996. In order to describe the performance of the air-conditioning system,the thermal climate and indoor air quality were determined. The air-conditioning system wasable to maintain the thermal climate within the range recommended in the ISO standard 7730for most of the time.

In residential buildings, air-conditioners are usually operated in intermittent mode. Thisintermittent mode may complicate many aspects of indoor environments. Indoor humidityexcess is a major problem, since humidity excess is associated with biological pollution andformaldehyde emission. This paper reports our monitoring of indoor air temperature andrelative humidity in a real life building in the hot humid Hong Kong climate. These monitoredresults indicate that, in residential buildings, occupants habits in using windows for naturalventilation exacerbate indoor relative humidity excess.

Three very different task/ambient conditioning (TAC) systems were investigated in a climate chamber. Two desk-mounted TACS, the “Personal EnvironmentalModule” (PEM), intended for US offices, and the “ClimaDesk” (CDESK), intended for European offices, were compared experimentally with a floor-mounted unit, the “Task Air Module” (TAM). All three provide some individual control of cooling, while PEM and CDESK also provide individual control of heating.