In order to understand why Mechanical Ventilation with Heat Recovery is common in some countries of Europe yet installed in a small minority of domestic dwellings in the UK, surveys of Regional Electricity Companies and distributors have been carried out to identify whether there are grants available to promote the system in the UK and what influences sales of the system across Europe. A review of other heat recovery systems is provided to assess whether they are competitiors.
Heat recovery is difficult to implement in passive stack ventilation because the pressure loss is usually too high in conventional heat exchangers compared with the stack pressure. Laboratory investigation and computer simulation have been carried out on a low pressure-loss heat recovery device based on heat pipes which is suitable for application in passive stack systems and other systems where a low pressure loss is essential. It was found that heat recovery efficiency decreased with increasing air velocity.
Numerous ground-coupled air systems have been constructed in combination with heat recovery units in mechanically ventilated buildings in Switzerland. The objective of this study was to investigate the microbial content within these ventilation systems and to monitor the quality of the air supply. The concentrations and the types of microorganisms in the outdoor air, in the air of the pipes and in the supply air of twelve groundcoupled air systems were determined. In addition, three buildings were examined four times a year to cover seasonal changes.
This paper presents a comparison of predictions from a duct efficiency model developed by the authors with measured real-time heating n, system efficiency measurements from six site-built residential homes with natural gas furnaces in the Puget Sound region. The model takes into account the interaction between supply and return side losses, the interaction between conduction and air leakage losses, the interaction rs between unbalanced leakage and natural infiltration, and the recovery of heat through the building envelope from ducts in various locations 1) within the home.
The performance of a heat-pipe heat recovery unit was tested in a two-zone chamber with a horizontal partition. Air velocity was found to have a significant effect on the effectiveness of heat recovery. The effectiveness decreased with increasing air velocity. Simulation of air flow was carried out for the test chamber under natural ventilation conditions. It was shown that a heat-pipe heat exchanger can be used to reclaim exhaust heat in naturally ventilated buildings to effect energy conservation.
In this paper, the conversion of exhaust heat to latent heat is studied as one of the methods for the preservation of the thermal environment in urban areas. A simulation model of exhaust heat management is composed and applied to the soot-and-smoke emitting facilities in the Tokyo Metropolitan Area. The effectiveness is estimated by indices of "coefficient of exhaust heat management" and "conversion ratio of exhaust heat to latent heat".
Ventilation systems with heat recovery offer several advantages such as, of course, energy savings but also the possibility to add acoustic and filtration treatment. This study was to evaluate the thermal performances of such systems for residential ventilation in France. These units usually combine exhaust and supply fans, filters and a heat recovery exchanger. To test them, a special draft is being written by the CEN experts of TC 156/WG/AH7.
The trend towards improving building air-tightness to save energy has increased theincidence of poor indoor air quality and associated problems, such as condensation onwindows, mould, rot and fungus on window frames. Mechanical ventilation 1 heat recoverysystems combined with heat pumps offer a means of significantly improving indoor airquality as well as providing heating and cooling required in buildings.This paper is concerned with the development of a novel ventilation I heat recovery systemfor the domestic market1.
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