ENERGY EFFICIENT HOUSING DEMAND CONTROLLED VENTILATION
Fan Power Consumption
MEV 1010 kWh PIV 950 kWh EXTRACT FANS 840 kWh PSV 900 kWh DEMAND CONTROLLED MEV 660 kWh MVHR 500 kWh DEMAND CONTROLLED PSV 600 kWh 100 200 300 400 500 600 700 ENERGY CONSUMPTION (kWh) Research showing most energy efficient ventilation systems in a three-bedroom home
has been calibrated at a UKAS accredited calibration centre. BSRIA Instrument Solutions is the only
UKAS accredited calibration laboratory for evaluating air volume devices with a test facility specifically designed for products used on domestic ventilation systems. However, said Gilbert, Instrument Solutions has to date only calibrated three hoods and anemometers not belonging to BSRIA for air volume. ‘So who is measuring compliance and on what authority?’ he asked. A recent Ventilation and Indoor Air
In SAP Q bench testing, MVHR meets
all the Code criteria for energy efficiencies but, in reality, an installation turns in different results from a SAP bench test carried out in laboratory conditions. The problem is that for the technology to deliver the high efficiencies seen in the SAP Q tests, the dwellings must be airtight – and this is not happening. At the Zero Carbon Hub conference in
February, ‘Progress towards 2016’, Alan Gilbert of BSRIA informed the meeting that in 2011 BSRIA tested approximately 7,500 properties for airtightness of which only 200 met the 2010 version of the Building Regulations. In 2012 he estimates BSRIA will test 8,000 to 10,000 properties of which 1,500 will achieve Building Regulations. He went on to say that according to The Domestic Ventilation Compliance Guide Section 5.2, measurement of air flows should be performed using equipment that
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Quality Task Group (VIAQ) report1 raises concerns about MVHR that need to be taken very seriously: ‘The task group considers that examples of failures in typical design, installation and commissioning practice are all too common and these will have the effect of reducing the performance of systems. Badly performing systems may not deliver the anticipated carbon savings and may result in degraded IAQ with related consequences for health.’ It also noted that: ‘Although good
control is essential to the correct operation of systems, good practice in the design and provision of controls is uncommon. Clearly this needs to be addressed. Realising good performance throughout the life of systems also requires that maintenance is undertaken in accordance with manufacturers’ requirements. The task group noted that many systems have been installed in locations, such as roof
September 2012 CIBSE Journal 47 800 900 1000 1100 1200 220 kWh 120 kWh 90 kWh 130 kWh
MVHR is in pole position simply because SAP has no methodology to measure DCV performance
45 kWh
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