Taking control of your renewable technologies
Published: 01 April, 2015
Good control strategies are vital to gain the benefits of applying renewable technologies. Truly open protocols and an intelligent approach are the keys to success. Roger Woodward explains why.
In spite of recent falls in the cost of gas, the use of building integrated renewable technologies in the UK shows no signs of abating. Figures from DECC show that 2013 was one of the best years yet for the adoption of technologies such as photo-voltaics, heat pumps, biomass and CHP.
Driven by legislation and incentives such as the Renewable Heat Incentive (RHI), designers, contractors and clients are embracing the benefits of low-carbon renewables. However, while the market is growing, we need to ensure that end-users of this equipment are aware of the importance of good controls for renewables.
Without applying well thought-out control strategies to building integrated renewables, customers may not be seeing the optimum performance from their investment. What’s more, good control can support other important areas such as maintenance, which will ensure the renewables element of the building services functions well in the long-term.
The first question to ask is whether the renewables (the CHP, the solar hot water and the heat pump) are integrated into the building energy management system (BEMS). It may seem obvious, but many controls installers have visited buildings and found that the renewables (whatever form that takes) are not connected to the BEMS.
Michael Kirkland, managing director of BEMS specialist Forest Rock, says, ‘I have seen that lack of integration on renewables. It can happen on large projects such as hospitals where designers have been ticking the renewables box by installing biomass boilers. But the renewables are not joined up with the rest of the BEMS.’
Alessandro DiDomenico, controls and performance engineer of heat pump experts GI Energy, says, ‘The controls strategy must be clear and ensure that the renewables work in harmony with the building services system to achieve the best performance.’
One of the reasons a renewable technology may lie ‘outside’ the building-management system is that different teams of installers work on the building services. The renewables specialists, who may not be controls experts, may therefore be left to their own devices to install and commission their equipment.
DiDomenico adds, ‘You have to understand controls and the requirements of the renewable technology you are working with. For example, the BEMS might have a set-point that is good for gas-fired boilers but that may not be the best temperature for the heat-pump system.’ He adds that GI Energy took the approach of installing its own controls that can interface easily with the BEMS because of these issues.
This experience highlights why open protocols are particularly important in these circumstances. It must be possible for the controls specialists to bring all the elements of the building services into a single system — to maximise the energy- and carbon-saving benefits of renewables. For example, systems that can make use of a truly open protocol such as the Niagara Framework (used by both GI Energy and Forest Rock), offer flexibility and are future-proofed so that options such as cloud-based data collection can be used if required.
Controls are vital to ensure that clients are making the most of the financial investment that renewable technologies often represent. Kirkland says, ‘We carry out a lot of solar-PV installations, and a large proportion of these have solar arrays which are only connected to a meter. This can cause problems, because there is nothing to track faults such as a failed inverter, and that means the client is losing revenue because the PVs are not generating energy, and could be a significant loss of income.’
Both DiDomenico and Kirkland highlight the importance of delivering information to the end-user in a useful and easily-understood way. And greater understanding of how the building is operating leads to energy savings and sustainability.
‘We work with clients to give them a highly usable graphical user interface (GUI),’ says Kirkland. ‘We keep the information suitable to each audience accessing the system, whether that’s the financial director, building manger or someone working in it. This way, building managers and operators can have the information they need, but occupiers can also see useful information too.’
GI Energy takes a similar approach, delivering information that is suitable for different groups of end-users. ‘We provide clients with a web-user interface as standard. They have a simplified page to access and change time clocks for example. We would also build a page for the engineers to carry out commissioning and perhaps an HMI display in the plant room.’
Ensuring that renewable technologies are part of an intelligent BEMS creates value in the long-term. This is particularly true where engineers can have remote access to monitor the system.
DiDomenico says, ‘We have found it useful to have remote access so that we can work on a continuous-commissioning basis. You can’t do everything in the first week of a new project. This way, we can analyse trends and tweak performance over time so that the benefits of renewables such as heat pumps are optimised.
And if there is one thing that can sabotage a sustainable building, it is uninformed occupants who may not be aware of why their building behaves as it does.
Kirkland says, ‘If occupants can understand how the building behaves because of good controls and good user interfaces, they are more likely to be “sustainable” occupiers. They understand that the heating may turn off to save energy, and not make that phone call to the FM to complain.’
Overall then, when considering renewables and building controls, the key message is one of integration. While the contract may lead to different installation teams working on the heat pumps or the solar-PV, good planning of the controls can knit the equipment together into an optimised system. Open protocols are key, as is the support of knowledgeable professionals.
Roger Woodward is managing director of Tridium for the UK and EMEA.
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