Combined Heat and Power (CHP) systems, also known as cogeneration, is becoming an increasingly desirable technology within the commercial heating and hot water markets as awareness of their potential benefit spreads. As an effective method of increasing a building’s energy efficiency and reducing emissions, CHP is a key technology to consider in the face of increasingly strict building standards. Due to valuable energy savings, it can also be a beneficial investment for end users. However, CHP systems require the proper application to realise their much-sought-after benefits, making careful system design essential to any project.
Suitable applications for CHP systems typically feature buildings with large domestic hot water demands and continual background electricity loads. Large schools, or those that include on-site leisure or sports facilities such as a swimming pool, therefore constitute an ideal opportunity to make effective use of CHP. Smaller schools can be well served by CHP when properly designed, and boarding schools and halls of residence are typically excellent applications as the daily needs of residential living creates a large demand for hot water, heating, and electricity.
Combined Heat and Power is the simultaneous production of thermal and electrical energy from a single source of fuel, and is a proven method of significantly increasing the energy efficiency of a building. Producing electricity by connecting an engine to a generator at the point of consumption can achieve similar levels of generation efficiency to that of a conventional power plant, while also eliminating the energy losses associated with transmitting power over long distances and contributing to the decentralisation of power generation.
The waste heat produced in the process is recovered through a series of heat exchangers and used towards the thermal energy demands of the building, minimising the amount of fuel energy that is lost in exhaust gases. By connecting the CHP appliance to a building’s hot water or heating system to pre-heat incoming water, a significant portion of the input energy demand is moved from away conventional condensing boilers to the CHP, thereby increasing the overall efficiency of the installation.
The Adveco TOTEM CHP is the first in a new generation of microcogenerators, featuring market-leading efficiencies and the lowest NOX and CO2 emissions available from any CHP within its class. Designed and built in Italy by Totem-Energy s.r.l., the TOTEM is the result of 40 years of continued research and development, and features components purpose-built for operation on natural gas. A 1.4-litre Fiat Fire engine, sourced directly from Fiat Chrysler Automobiles – the developers of the original TOTEM in 1978 – and an ECU supplied and tuned by automotive experts Magneti Marelli allow the TOTEM to achieve unparalleled cogeneration quality and reliability. With NOX emissions at <12 mg/kWh, 95% lower than the upcoming 2018 Ecodesign standards for clean CHP at 240 mg/kWh, the TOTEM is leading the way in environmentally-conscious building design.
While the benefits of CHP are clear, it is important to consider that they are only available when the system is operating. It is therefore desirable to design systems to achieve the maximum number of run hours possible to achieve the greatest energy and financial savings from CHP. In the UK, an average school building will require a level of heating for approximately two thirds of the year, shutting down only during the warmest summer months, creating a seasonally consistent LTHW demand. While occupied, schools also present a constant domestic hot water demand from sources such as sports showers, science, arts & craft, and home economics classrooms, plus bathroom use throughout the day, in addition to peak demands for mealtime preparation.
Combined, this becomes a viable application for CHP. By connecting a buffer vessel to a CHP appliance that feeds directly into a central heating header, a differential temperature control system can be used to monitor central heating return flow temperatures to activate the CHP and associated pumps when heat input is required. By pre-heating the central heating return circuit, the CHP can achieve high run hours and significantly reduce the heating load on conventional boilers. Furthermore, as schools also exhibit a continual demand for electricity, the power generated by CHP can always be used on-site, reducing the reliance on grid-supplied electricity.
For larger schools and for those that include extensive leisure facilities such as swimming pools, the thermal energy demands are sufficiently high that an uncontrolled system is instead viable. In such an application, a constant background heating load means that the CHP can run almost continually and the produced heat and power can always be used on-site towards a fixed LTHW demand.
Since the launch of the TOTEM in 2015, Adveco Ltd. has supplied a number of schools and higher education accommodation buildings with CHP heating and hot water systems. With each application receiving a bespoke design from an in-house application design department, the effectiveness of CHP has been maximised. A recently commissioned installation at a large boarding school is achieving run hours averaging over 20 hours per day, on track for over 7,400 hours per year, with expected annual savings, inclusive of maintenance and servicing expenses, in excess of £21,500. Similarly, a school sports complex fitted with an Adveco T20 CHP in late 2016 has achieved peak run hours of over 23 hours per day in a demand pattern that is expected to continue year-round.
Adveco Ltd. is a supplier of building services mainline solutions and specialists in commercial hot water solutions. Adveco Ltd. is the sister company to Adveco (AWP) Ltd. who trade as A.O. Smith Water Heaters in the U.K. and has over 45 years of experience in the building services industry.
With an ethos to provide only the highest quality products and services, including some of the latest renewable technologies available such as solar thermal and CHP systems, Adveco Ltd. manually design and supply complete hot water and heating solutions. Incorporating a professional application design department to envision bespoke and practical systems, in addition to in-house sales, servicing, and commissioning engineers, Adveco prioritise the needs of the client and the application to deliver the most efficient, cost-effective, and reliable solutions available.