SPECIAL FEATURE HVAC Leading manufacturers will ensure that their products are energy efficient. for hot water provision as their larger counterparts, are now available. Slim fit models that feature an internal expansion system mean a faster and neater installation, and save on space as they fit neatly into compact storage areas. These are an ideal recommendation for customers with high hot water requirements, but minimal space available. Efficiency Another common consumer concern is energy efficiency. As homeowners become more conscious of environmental issues, the demand for eco-friendly products is growing. For these customers, the first port of call is solar energy – but what are the options available? Solar thermal cylinders are a popular solution. These models balance solar heated water capacity with immersion or boiler heated supply, helping to keep energy bills down while maintaining a reliable source of hot water. What’s more, solar ready options are available, carving a route to solar thermal hot water in the future. Here a solar thermal cylinder can be installed, ready for solar collectors to be fitted in the future. Alternatively, for homeowners who already have, or are looking to invest in, solar PV panels, new products have recently been introduced which can utilise excess energy from the panels for water heating purposes. The UK is installing solar panels faster than any other European country. Around 877,000 homes in the UK have solar PV roof panels installed, with almost 4,000 installations carried out in April 2016 alone. However, it is estimated that in 50 per cent of properties, all of the power produced by the PV panels is not being consumed. This is because electrical appliances and lighting are not being used during daylight hours when electricity is being generated, because properties are generally unoccupied in the daytime. In response to this, manufacturers have designed cylinders which can use this surplus electricity to heat hot water, free of charge, reducing utility bills. With such systems, any power that is generated in addition to the household’s normal requirements will be diverted to the cylinder, rather than being sent to the grid. The water will be heated to the desired temperature, controlled by a thermostat, ready for the household to use when required, with high performance insulation keeping the water hot. To avoid any draw from the grid, a ‘buffer’ of energy will be retained; typically, if there is 2.2kW of export energy, the controller will divert 2kW into the cylinder’s immersion heater, leaving a 200W buffer. This does not affect the property owner’s FiT Generation payments; where there is a ‘deemed’ usage contract the export tariff is paid whether the energy is consumed or not. Where an export meter is fitted the benefits can still outweigh the costs of water heating. Up to standard Finally, no matter what type of cylinder is selected, contractors should seek out cylinders that have been constructed and tested to established British and European standards, as well as being manufactured in a factory which has accredited Quality Management Systems. Third party approvals – such as WRAS and KIWA – demonstrate good quality and performance. As our lifestyles change, and the average hot water requirement soars, demand for unvented cylinders is certain to increase. For electrical contractors looking to capitalise on this, developing an in-depth knowledge of the key features to look for in a cylinder, and the models available, is essential. Alan Clarke is Heatrae Sadia’s technical support manager and has worked in the water heating industry for 38 years. Alan represents Heatrae Sadia on various trade associations including the Hot Water Association and BEAMA. He also represents trade associations on various BSI Technical Standards committees, MCS Solar Thermal and Heat Pump groups and European standards committees, as well as BEAMA on UK water heating issues at CECED.