With the anticipated 15% increase on fuel prices over the next year, more and more pressure is being put on builders, architects and developers to build sustainable and energy efficient buildings. Peter Gammon, Technical Product Manager at MHS Boilers, takes a closer look at how installers and specifiers can do more to support a low carbon UK.
Without wishing to steal any of Kirstie’s (Allsopp) or Phil’s (Spencer) thunder, when it comes to creating and maintaining the energy performance of buildings, it is all about location, location, location. By this, I mean that everything from the climate, shading and wind speed can all influence the supply of heating and hot water to a building.
As energy costs rise, many architectural and building services firms recognise the value of reliable and sustainable energy management in industrial, domestic and commercial buildings, during site analysis and development. Of course, the revised Building Regulations, BREEAM ratings, and the Code for Sustainable Homes and localised planning policy have all played their part in encouraging experts to look at better ways to deliver new buildings. Architectural and landscape designs should always be closely integrated and, if possible, the layout of each site should provide wind breaks in cold winters and in an ideal situation accord access to cooling breezes in the summer.
So what are the issues involved in providing efficient heating and hot water in domestic and commercial buildings and how can installers and specifiers support the work of architects and M&E consultants in delivering sustainable heating and hot water?
Well, first of all, it would seem that the climate in the UK is getting warmer. Global average temperatures are expected to rise between 1°C and 6°C during the coming century, with the greatest increases in temperature taking place at high latitudes.
Therefore, to gain the maximum benefits from the local environment, building design must ‘fit’ its particular climate. For example, site selection, layout, shape, spacing, orientation and their mutual relationships will all affect the thermal and energy performance of buildings. When they are specified and installed correctly, significant volumes of hot water can be generated from renewable sources reducing utility costs and the dependence on fossil fuels.
A well-designed solar thermal system can provide between 50% -70% of the DHW needs of a building; up to 100% in the summer months and 5% – 10% in the winter months. To get the most from flat plate or tube collectors, it is important for architects and designers to be mindful of shading and the likely effect upon solar collectors at the site analysis stage.
Consideration should be given to future effects of young trees around the building which will grow and overshadow the solar panels. Neighbouring buildings which may cast shade must also be considered when deciding where to position the collectors. Another very important point is orientation of the building relative to azimuth zero; it’s disappointing when you find that the most available space for the installation of solar collectors is facing in an unfavourable direction. Without careful planning, these elements can impact greatly on system potential.
Effective heat sources
Heat pumps are also growing in popularity and one reason for this is that they can supply as much as 4kW of heat output for just 1kW of energy input. It is important to bear in mind during site planning and analysis that, under certain conditions boreholes are incredibly effective heat sources for heat pump installations. This approach is very common in many European countries, and is the preferred method of extracting low grade heat from the ground.
Geothermal boreholes are typically 50 to 100m deep and approximately 150mm in diameter, so consideration at the planning stage of any development is essential. The number of boreholes required for a given sized heat pump also depends on the underlying geology. As with all installations of ground source heat pumps, design of the ground collector (borehole and probes in this case) is critical to the long-term efficiency of the final installation. To get the best from heat pumps it is important that this is considered and decisions are made at each stage. It is therefore vital to consider geology, site surveys and location as part of the initial site analysis.
At MHS we have a variety of heat pump systems available – from water source to ground source and air source and we can work with consultants from the start of any building project to advise on the best types of heating and hot water systems to maximise performance and energy efficiency.
But what about the humble boiler when it comes to site analysis? The biggest pitfall, particularly with commercial buildings with a load of greater than 150kW is chimney heights and consideration at an early stage about flue siting is strongly recommended.
To help meet more and more stringent rules and regulations for commercial buildings, working with consultants and installers as early as possible, is an effective way to achieve optimum efficiency of the heating and hot water services, as well as its overall environmental impact.
For example, we recently worked with an architect and building services consultants on a development, Horizon House, the Bristol Headquarters of the Environment Agency, to deliver the highest score ever awarded by the Building Research Establishment (BRE) for its environmental credentials.
Built by Sir Robert McAlpine, the building uses the latest technology and innovative design to ensure the highest levels of environmental performance in both the construction and use of the building. The environmental standards were very stringent and the products specified, including MHS Boiler’s Ultramax R600 boilers, were selected to deliver the kind of performance and efficiencies needed. Each model was equipped with two return connections as standard, allowing high efficiency to be achieved when serving a mix of higher and lower system load circuit temperatures.
Finally, carbon reduction targets are here to stay, so it is important to work closely with our building services partners, specifiers and consultants to reduce the reliance on fossil fuels and look for greener and cheaper options at the site analysis stage.
This can only be consistently achieved if all of those involved recognise the value of working together for mutual benefit. What is it they used to say? ‘It’s good to talk’. And that can make a real difference when it comes to the development of sustainable and energy efficient buildings.