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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Domestic Passive Ventilation with Heat Recovery (PVHR): Performance Criteria, Tests and Operational Variations

Get access (open in a dialog) DOI: 10.1615/IHTC15.ees.009883
pages 2299-2313

Abstract

Historically, housing in general has had low levels of insulation and poor airtightness. Although this characteristic was not energy efficient it provided a plentiful supply of fresh air. Over the last twenty years insulation and airtightness of homes has received attention due to a global drive towards energy efficiency and carbon emissions reduction. Since a large portion of energy used in homes is utilised for comfort heating or cooling, the focus has been on improvements to insulation and airtightness in order to decrease the dwellings' total energy use, as well as ensuing carbon emissions. However, a large body of research shows that airtight houses require adequate air management (controlled ventilation) to prevent the occurrence of poor indoor air quality which can contribute to illness such as asthma as well as the so-called sick building syndrome.

Introduction of controlled ventilation presents another energy related challenge - fresh air introduced to homes needs to be re-heated (or cooled) adding to energy use and negating most gains resulting from improved insulation. Even if Mechanical Ventilation with Heat Recovery (MVHR) is used, the systems use electricity and require maintenance to operate, adding to cost and reducing energy savings. Thus an air management system that can improve building ventilation, prevent excessive heat loss and use no energy in operation is a desirable option. The Ventive PVHR technology, described in this paper, can be such an option that provides efficient ventilation with heat recovery and no electricity use. This system utilises both thermal buoyancy and pressure caused by the wind-driven Pitot effect of a cowl as its two driving forces.

Advances in heat exchanger design resulting in interleaved coaxial heat exchanger units allow the thermal energy of air to be exchanged to the cooler inlet air with consistently high efficiency and negligible pressure drop. Thus heat loss due to air ventilation can be minimised and the running costs avoided. This paper focuses on a series of effectiveness assessments of the PVHR technology. The PVHR system, fitted into an airtight and insulated test room, has been tested replicating different housing types and under different environmental scenarios. While a preliminary study has previously explored the system effectiveness with regards to the heat transfer, this paper conducts further assessments to determine the system's performance in a wide number of practical installations.