Article from: Energy in Buildings & Industry Magazine – June 2012
Coming out of the Shade While the Feed-in Tariff has grabbed the headlines, the Government has launched a similar scheme for non-domestic solar heating. Stuart Elmes looks for the best opportunities.
At the end of 2011 it seemed that photovoltaic solar energy (PV) was always in the news, with legal challenges to the Government’s management of the Feed-in Tariff (FIT) and a rush to install before tariff rates dropped. Among all of this, it would have been easy to miss the fact that a similar cash-back scheme for renewable heat technologies, including solar thermal, was launched in November.
The Renewable Heat Incentive (RHI) supports the installation of biomass heating systems, heat pumps and solar thermal systems, as well as the combustion of biogas, in all buildings except single domestic premises. In the case of solar thermal, it pays the owner of the system 8.9 pence per kilowatt-hour (kWh) of useful heat, with the tariff index-linked over the duration of the scheme. The system owner can claim the cash-back every quarter for 20 years from the date of registration.
Eligible buildings include commercial buildings or groups of houses or apartments served by a single communal solar system. Single domestic buildings are intended to come under the scheme during summer 2013, with a consultation expected to be launched this September.
Attractive heat load – Any building that has a need for hot water provides an opportunity to deploy solar thermal, but some buildings have a heat load that is more attractive than others. These include:
- Residential: Accommodation blocks for boarding school pupils, university students and junior hospital staff often have a centralised plant room where water is heated for distribution around the building. It can be relatively straightforward to install a solar buffer tank to pre-heat the water before it is passed on to the existing heating system, which can top up the temperature on days of low solar energy. Sheltered accommodation and care home buildings are often heated in the same way, and if residents are assisted to bathe during the working day, then a smaller solar buffer tank can be used, reducing the capital costs. Apartment blocks can pose a more difficult challenge to the integration of solar water heating, especially if each apartment has its own individual heating system. However, solar heating systems which generate heat from a communal solar array and distribute it to individual apartments via a ring are now possible.
- Leisure: Hotels often have a high water demand. If the occupancy of holiday accommodation is seasonally biased towards the summer months, then the effectiveness of a solar system is increased because the supply better matches the demand. Swimming pools are also an excellent application for solar heating because the low demand temperature means the solar panels are more often working at maximum efficiency. Coupled to this, the large thermal capacity of the pool allows the full use of energy on sunny days, where storage capacity might limit the energy collection for a domestic hot water system.
- Health Care: Hospitals and surgeries can have a constant high demand for hot water, and are therefore very suitable for solar heating.
Enormous Potential: An EU research programme, So-Pro (http://www.solar-process-heat.eu), identifies an enormous potential for utilising solar in industrial applications. Many national markets across the EU boast levels of solar thermal deployment for residential buildings which leave the UK far behind, but when it comes to industrial applications, we’re all just getting started.
The RHI is the first scheme of its kind in the world, and could act as a real driver for businesses that use heat in their industrial processes to consider using solar thermal to reduce their dependence on fossil fuel energy, saving on bills and getting cash-back from the Government for doing so.
So-Pro estimates that 30 per cent of total industrial heat demand is at temperatures below 100˚C, and may therefore be suitable for solar heating. The programme highlights a number of case studies where solar energy was successfully deployed in an industrial setting:
- Food industry: A producer of dried meat in Jerez de los Caballeros, Spain, installed a 250m solar thermal array to heat 30,000 litres of hot water storage for washing processes in production, and for cleaning of vessels and machinery.
- Metal processing: An electroplating company in Rahden, Germany, installed a 220m solar array to support the heating of the galvanising baths to 80˚C.
- Drying: A brewery in Neumarkt, Germany, installed 72m solar array to preheat air for drying processes in the malt house.
- Washing: A specialised truck washing company in Villamuriel de Cerrato, Spain, installed a 140m solar thermal system to heat water for washing tankers used to transport chemicals, food and industrial oils.
- Preheating steam make-up water: A laundry in Marburg, Germany, installed a 57m solar system to raise the temperature of make-up water feeding two gas-fired steam boilers.
The successful implementation of these bespoke renewable energy installations was found to require close cooperation between M&E contractors with a detailed understanding of their customers’ heating processes and technically competent solar suppliers or installers that could ensure the design achieved efficient use of the solar technology.
With the advent of the RHI, the stage is set for heating companies to help their customers cost-effectively reduce fossil fuel use in a wide range of commercial heating applications.
