Energy efficiency – are we competent?
You can invest in the most energy efficient and sophisticated products on the market, and they are available in abundance, but this can all be wasted if someone just opens the window because they are too hot.
The efficiency comes not only from the product, but also from the way in which it is used and controlled so the task for system designers is to put the energy consumption information directly in front of the client or end user.
At the moment the industry is trying to increase energy efficiency by regulation, with the Part L regulations Energy Performance in Buildings Directive and the soon to be Energy Using Product Directive. All very admirable pieces of legislation, but they probably won’t change the behaviour of building occupants!
First there was an emphasis on the components within systems, and now there is the emergence of an interest in integration of those systems. This in itself doesn’t guarantee efficient operation as you can end up with separate control systems fighting against each other, each vying to achieve optimum performance and not quite getting there for example – modulating condensing boilers operating in isolation of modulating pumps.
Some of these problems have been recognised in the USA, where the introduction of Bacnet protocols embedded within products allows cross product communication on a common platform. In particular, where microprocessor systems are involved the integrated operation is totally dependent upon the micros being able to communicate effectively with each other. Within building services this has historically led to sophisticated sub-systems under the control of a Building Management System (BMS) switching the equipment on and off rather than actually meeting the level of demand. In the heating industry the transition from modular on/off boilers to high/low, and latterly, modulation, has left behind some of the old established step control methodologies still being used for the management of cascade functions.
Some of the better known BMS providers have utilised 0-10 volts to drive the level of demand, but there are still a lot of systems out there which simply say switch on, switch off. Because of the development in product standards, particularly in the heating industry, lower levels of modulation and resultant improvements in heat exchanger design are providing significant improvements in efficiency and energy gains.
Boiler manufacturers providing dedicated cascade management systems, including peripheral sensors, have instigated this to optimise system efficiency by controlling the level of modulation.
The benefit to the client is lower cyclic frequency resulting in long term, reliable operation. More importantly today, with the advent of condensing boilers providing multi zoned and multi temperature circuits, the controls can deliver the zone demands crucial to supplying the required comfort levels.
A requirement for commercial building systems over 100kW to implement energy monitoring and targeting could be as simple as point of use gas consumption, or as sophisticated as full energy trend reporting. The object being to make information visible in the hope that it would influence consumption.
There is also developing interest in utility metering. With the publication of the Energy White Paper and the implementation of the latest building regulations, the UK government has committed to placing metering at the heart of the energy efficiency debate. Historically it has been the role of the BMS to coordinate energy usage from remote devices, but today with the developments in digital technology it is possible to have real time system information delivered directly to a desktop.
In the case of modulating boilers, detailed information can be available on both operational status and performance parameters. Based on this performance information the client can obtain comprehensive duty data. An additional benefit of this detailed information is that it is also available to a maintenance engineer to assist in fault diagnostics or predictive maintenance regimes. With access to this, either local or remote bureau control of multi sites can be simple.
At a local level there is commitment to implementing renewables into buildings. Obviously the task for building designers is to integrate them into mainstream utilities, all of which needs an element of control. In the case of boilers, the integration of solar thermal solutions into existing domestic hot water storage systems can be managed directly by some boiler controls. But how we in the industry get renewables and condensing boilers working together as an integrated system is still a question to ponder.
There is still a lot of work to be done in the industry to ensure that the products we currently have can be brought into the mix with renewable technologies and therefore we still have work to do to produce the kind of energy efficiency and savings that need to be made over the coming decades.