Mechanical ventilation with heat recovery (MVHR) and passive stack ventilation (PSV) systems are both proposed as methods of ensuring satisfactory ventilation rates in UK housing. MVHR provides controlled ventilation in all rooms together with heat recovery, while the cheaper PSV system offers lower running costs, but without heat recovery and without a controlled air supply to all rooms. The relative energy consumption of the two systems depends on a number of factors that are difficult to predict.
Dynamic insulation stands for an insulation through which an air flow flows. The air flow is usually the normal ventilation flow. The air can flow in the same or in the opposite direction of the normal heat flow. The dynamic insulation can be arranged as single where only inlet or exhaust air passes the insulation, or as combined where inlet and exhaust air pass one half of the insulation each. Dynamic insulation using exhaust air might result in condensation problems in cold climates.
The continual reduction of the transmission heat losses of residential buildings causes an increasing importance of the ventilation heat losses. Energy saving can be achieved by using a mechanical ventilation system with heat recovery. A great improvement is the combination of heating and ventilation in one system. In this project such a combined system was developed to reduce the energy consumption of the fans, the operating expenses and also the investment costs in comparison to existing systems. In future a high market acceptance is expected for combined heating and ventilation systems.
Total energy exchangers with a rotating heat storing matrix have been applied to air conditioning systems for more than 25 years with very good results for saving both heating and cooling energy. The efficiency of the hygroscopic coating of the rotors is very important to recover the latent energy, but there is the risk of cross contamination. To prevent odour transfer, the mechanism of the sorption and desorption process has to be investigated in detail.
Ontario Hydro expects that about 25% of its generating plants will have retired by the year 2014. Rather than simply building new generating plants Ontario Hydro wants to diversify its approach by reducing growth in demand as well as increasing supply. Heat recovery is one of several demand-side options with potential for displacing electrical energy in buildings. Where space heating, cooling and service water heating in existing buildings is provided by electricity, savings both in electrical energy and demand are possible through heat pump heat recovery.
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