Continuing Professional Development Photovoltaic panel installations

ICB (Projects) Ltd installed a 36kWp solar PV system of thin-fi lm modules, which could generate £250,000, on the conference centre at the National Farmers Union HQ at Stoneleigh Park, Warwickshire, built by Thomas Vale Construction in 2012

ICB (International Construction Bureau) Ltd is one of Britain’s leading suppliers of sustainable, environment friendly roofi ng systems. ICB roofi ng products are tested and

certifi ed to the highest standards of excellence, supported by industry leading warranties and full technical back up. The company’s mission is to supply sound and sustainable solutions for the waterproofi ng of roofs with the emphasis on environmentally friendly products and systems.

monocrystalline cells. However, in today’s market all modern panels have a similar effi ciency and price point. Some manufacturers combine crystalline and thin fi lm technologies to create panels that are up to 19.4% effi cient and some premium manufacturers now have monocrystalline panels available which push this effi ciency up to 21.5%. It is also possible to increase the power

generated by a PV cell by using a concentrator system to focus more sunlight onto its surface. However, this is not widely used, and does not necessarily make a system more cost effective. PV arrays generate electricity as direct

current (DC) that must be converted to alternating current (AC) before grid connection. Conversion from DC to AC is

“As a rule of thumb, solar PV systems have a payback period of eight years. From then on they produce energy and profi t for the owner”

achieved by an inverter and, as all inverters use a proportion of the electricity generated to operate, there is usually a loss of some 5% of the energy generated. Once installed, PVs offer a simple

method of meeting targets for energy reduction and in this respect alone will add value to the building. As a rule of thumb, solar PV systems have a payback period of approximately eight years. From then on they produce energy and profi t for the owner of the system and, with a life expectancy of 25 years, this can add up to substantial sums. At present solar panels also count as

credits when designing to Code for Sustainable Homes at levels 3 and above, although this standard is due to be wound down in 2015.

If designing to be zero carbon, all new solar installations should be specifi ed to meet a building’s peak demand as a signifi cant proportion of the electricity it generates at times of non-peak demand is likely to be exported from the building to the National Grid. The proportion that is used in the building will depend upon the patterns of electricity demand. A high “load factor” signifi es an average demand that is near to the peak demand – i.e. something relatively consistent. A building with a high electricity load

factor would consume a higher proportion of electricity generated by a PV array designed to meet its peak demand than a building with a low load factor. However, in both cases, a greater proportion of the electricity generated would be used on

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