Controls that are certified to reduce energy consumption
The effective control of building-services plant and systems can considerably reduce energy consumption, and the most effective controllers are those certified by eu.bac, as Harry Swinbourne explains.
Residential and commercial buildings are responsible for over 40% of all primary energy consumed across Europe. As part of European commitments outlined in the Kyoto Protocol, the European Energy Performance of Buildings Directive (EPBD) and its national implementations demand proof of energy efficiency, in the form of tests and certification, to prove products and systems meet standards for energy efficiency.
A European quality-assurance system for home and building automation helps establish a clear and fair process for driving standardisation, testing and certification. In response to the challenges set out in the EPBD and customer-led demand for more energy-efficient buildings, the leading international suppliers of building automation systems have established the European Building Automation & Controls Association: eu.bac.
The eu.bac association has now launched its European certification scheme (eu.bac Cert) for building automation products.
The association assumes primary energy consumption by buildings can be reduced by up to 25% by applying optimised building technology. Through eu.bacCert, installers are assured that the energy efficiency of certified products has been confirmed by independent test facilities and can be achieved beyond the borders of individual countries. The first version of the certification scheme covers individual zone controllers for radiator heating, fan coil heating/cooling, chilled ceilings and electrical heating devices.
A eu.bac certification (eu.bacCert) is based on two European standards: EN 15232 defining the effects of building automation and control systems for energy efficiency; and EN 15500 governing product standards with energy-efficiency criteria.
Certifying a device to eu.bac involves compliance with various regulations. Testing for eu.bac certification is conducted by an approved, independent testing facility. It includes measuring, documenting and certifying the control accuracy. Product testing is accompanied by audits of production locations to establish that they are capable of ensuring reproducible quality. Generally, to pass this inspection, manufacturers need to apply a quality-management system complying with (at least) EN-ISO 9001.
After successful completion of tests, a recognised certification body issues the product with a certificate carrying a licence number. Certified products bear the eu.bac certification mark (eu.bac Cert), indicating that they exhibit assured levels of energy efficiency, performance and quality.
In fact, eu.bac goes further than European standards require by demanding 30% higher control accuracy for zone controllers than the corresponding European EN 15500 standard. Products from individual manufacturers can exceed this figure; tests have shown that the Serval zone controller from CentraLine exceeds the control accuracy requirements of the standard by 400%.
At present, eu.bac currently certifies only individual zone controllers. This focus is because a very high savings potential of up to 30% is possible in commercial buildings with individual zone controllers, compared to buildings without such devices.
Many other factors also play a role in the energy-efficient performance of a commercial building, such as its fabric. Significantly, metering and optimised control technology of HVAC and hot water systems enables energy efficiency to be increased by up to 25% . Therefore, eu.bac is planning the release of a certification scheme for outside temperature compensated (OTC) controllers. A savings potential of up to 25% is expected compared to systems without OTC control. While the total savings achieved by OTC control and individual zone control are not necessarily the sum of the savings achieved by the two parts, eu.bac nevertheless estimates their joint savings potential to be 32%.
As stated above, Serval exceeds the control accuracy requirements of the standard by 400%. Yet its potential for improving energy efficiency is greater than that due only to high accuracy. When used together with plant controllers in a CentraLine system, it can send demand signals to the pre-control circuits for the hydraulic circuit to which it is connected. This allows an entire floor to be switched off if none of its rooms are used. As the pre-control circuits can signal to the boiler and chiller controllers, only the absolute minimum of heating/cooling energy is produced.
Integration in third-party systems is also possible. In a hotel, the room controller can, for example, be connected to the hotel reservation system. On the day the guest arrives, the controller automatically switches into standby mode. When the guest checks in, comfort mode is activated. When the guest checks out, if there is no immediate reservation for the room, it can revert to a low-energy state. This ensures an ideal temperature on arrival for guests and saves energy for the hotel.
In all buildings, the greatest energy savings will be achieved by working with a partner company which can design, install and commission a controls system that takes account of all the possibilities. These initiatives may include time programs, optimised start/stop functions, demand-driven energy production, the best control parameters, optimum system dimensioning, correct hydraulic comparisons and much more.
Harry Swinbourne is UK & Ireland sales director for CentraLine Building Automation at Honeywell.
