Power grab19 March 2014
Managing your factory's energy usage effectively can pay real dividends in terms of money (and planet) saved, and reputation (and comfort) enhanced, says Ian Vallely
Energy management is something of a 'Cinderella' service – out of sight and out of mind. The trouble is ignoring it will also leave you severely out of pocket.
For Gareth Stace, head of climate & environment policy at EEF, the prize for manufacturing companies of getting energy management right is significant. However, he does acknowledge: "Managing higher energy costs while maintaining international competitiveness is one of the biggest challenges facing manufacturers today.
"The most advanced companies are systematically addressing inefficiencies in their buildings and processes to try and mitigate rising costs that come straight off the bottom line."
Indeed, effective energy management can save your factory tens or even hundreds of thousands of pounds. The question is: how do you achieve it? Effective control is one answer. It will slash your running costs, typically by 15 to 35%; it will also cut energy consumption and pollution associated with energy use; improve comfort; limit wear and tear on building systems and plant, and minimise maintenance, repair and replacement costs.
Here are five steps to help you navigate the road to more effective energy control:
1 Gain an understanding of building controls: Building controls manage the operation of heating, ventilating and air conditioning (HVAC) systems, and, sometimes, lighting. They come in a variety of forms, including, says the Building Research Establishment (bit.ly/1l5MXGF):
- Demand control, which ensures the HVAC continues to operate until heating/cooling demand is satisfied.
- Sequencing, which can be a stand-alone control or via a building management system (BMS)/building energy management system (BEMS). Sequencers control the number of boilers required to meet the heating load of the building.
- Weather compensation, also known as variable temperature control. It controls the indoor temperature of the building independently of increases or decreases in outdoor temperature.
- Boiler load optimisation, a stand-alone control to prevent boilers from 'dry cycling' (firing when not required), reducing energy costs. Boiler optimisation can be programmed as part of the BEMS.
- Optimum start/stop, which enables a time schedule to be set up to control plant and equipment to fit in with the occupancy times of a building. This time schedule is also used to provide optimum start and stop of the HVAC equipment to ensure comfort conditions are achieved for the start and finish of occupancy.
- Occupancy controls, typically used in lighting systems and fast-response extract fan systems in bathroom areas. Heating and cooling systems tend to be too slow in their response to be effectively controlled by occupancy sensors. However, occupancy sensors can be used in meeting rooms and cellular offices to control fan coil unit fans and/or air conditioning units. There are four main sensor types: passive infrared, ultrasonic, microwave and audio.
- Interlock controls, which prevent unnecessary energy use and plant operation. For example, if doors or windows are opened, the interlock controls prevent the boiler(s) or air conditioning from operating.
- Building management system (BMS), a computer-based system that integrates building services such as HVAC, fire, security, power systems and lighting.
- Building energy management system (BEMS), a computer-based approach to measuring, monitoring, managing and analysing the performance of building services.
A BEMS improves plant control, monitors and displays energy consumption, and optimises equipment operating schedules. Karen Fletcher, executive officer at the Building Controls Industry Association or BCIA (www.bcia.co.uk), explains: "It gathers data from sensors, for example, light detectors or sensors that track occupancy, temperature, pressure, humidity or occupation within occupied areas of the building to create and retain a comfortable indoor environment."
However, if your plant operates a set shift pattern you probably won't need a full-blown BEMS. Many factories, says Malcolm Anson, managing director of Clarkson Controls (www.clarksoncontrols.co.uk), employ direct-fired gas heaters to keep their occupants warm "and you'd quickly know if there was a problem because people would get cold and complain".
He adds: "At most, a factory with warm air heaters might have a simple alarm, say a flashing light underneath the heater, to alert the factory manager to a problem."
Having said that, a BEMS can be useful in a factory if the HVAC equipment is difficult to reach, say above machinery. Anson reflects: "Its use also depends on the sophistication of the site. There might be a need for logging in a pharmaceutical or food processing plant or food factory, for example, and a BEMS can help with that."
2 If your factory has a building controls system/BEMS, evaluate it:
The BCIA recommends:
- Involving the people who monitor and use the control system regularly. They will be able to tell you how the system operates from their point of view. For example, they will be able to spot what features would be useful, but are currently missing.
- Involving the contractor who is maintaining your building controls. If you are considering the possibility of an upgrade, you may also find it useful to get a second opinion.
- Undertaking a technical assessment of the control system, including the design requirements, control strategies and physical equipment in your building that requires control.
- Documenting changes and observations from the evaluation process. So assess how well the control system currently operates; any training requirements for users; potential cost savings from re-commissioning existing plant; cost-benefits of upgrading (including the financial benefits of improved energy efficient control and operation).
The evaluation will place you in a strong position to understand the system and to draw up a list of what is needed to make it better. This may include training for control system users.
For Anson, it pays to adopt the KISS principle – 'Keep it simple, stupid'. He says: "So, for example, make the switching user-friendly with simple switching rather than complicated LCD screens showing superfluous information."
The first step to operating efficiently is identifying the controls on site through an audit. The BRE suggests asking: what controls do I have? What do they control? How are they controlling? What is their functionality? Are they integrated?
It adds: "Existing controls may have capabilities and functionality that are not being used, or the user may not be aware they are there (for example, the functionality for metering) or may be implementing functions within controls that measure the utility use in the building.
"This approach will enable meters to be mapped within the system, enabling the user to record consumption and identify areas to improve energy efficiency, and to verify any energy efficiency investments. Existing controls may have a built-in ability to provide additional plant control, such as boiler sequencing, weather compensation and demand control."
3 If you don't have a building controls system/BEMS, identify areas for saving and decide what you need: It's unlikely you'll have the budget, time or need to install an all-singing, all-dancing BEMS so think about different levels of control and areas where you can save the most money.
For Honeywell (bit.ly/1if6eYB), you will need expert help to make the right technology choice, minimise management risk and ensure compatible technologies/integrate them onto a single platform. Indeed, says Honeywell, choice of partner is just as important, if not more so, than choice of technology. The starting point for choosing the right partner is to ask:
- What system will work best in my environment to meet my needs?
- How complex are my requirements and how critical is the system to my business?
- How is this system delivered and how will it be maintained and upgraded over time?
- Who will be the most cost-effective and technically-expert partner over the long term?
And one more thing – ensure your system is expandable to accommodate possible future expansion. Ian Ellis, marketing manager of Siemens (sie.ag/1otKaHn), says: "Ideal here is to use an open protocol system using BACnet, for example. This can make you vendor-independent. It also helps in linking different building services back to the BEMS as many items now use open protocols (chillers, lighting, meters, variable speed drives, etc)."
So, if you do decide to specify a BEMS, choose a system or components that is/are compatible with other systems or components. According to Honeywell, that means selecting one of three system types:
- Open protocol: Where the BMS can communicate with field controllers using openly-available, industry-standard protocols, which allow users to select system components from a wide range of suppliers.
- Multi-vendor: Where the system developer/manufacturer certifies selected vendors as system integrators for their products, who are then able to supply, commission and service the system using specially licensed software tools giving building managers a choice of suppliers.
- User-managed: Where the system contains the software tools such that, with appropriate training, a licensed end user or their nominated service providers can service and maintain the system.
These concepts are, according to Honeywell, largely independent, although: "It is possible to have an open-protocol system which may or may not be multi-vendor, or it is possible to have a user-managed system which may or may not support open protocols."
The company has produced a document designed to clear up any confusion around the different types of system (bit.ly/1dI3nQu).
Anders Norén, managing director of Priva UK (www.priva.co.uk), adds: "As a factory manager you may want to look at systems with which you can retain as much of the existing infrastructure (cabling, sensors, field equipment, and so on) as possible and only change the brains in the system and then re-commission it… If you do that, it is going to be much more cost effective."
4 Implement a proactive maintenance regime: Siemens' Ellis explains: "Too often, BEMS systems are neglected in operation and they drift away from optimum performance, leading to inefficiencies and possible energy wastage."
Priva's Norén agrees: "Regular checks and updates are important to ensure that the system is managing and controlling the installation in the most effective way. The question is, who would do that? It could be the factory would be happy to subcontract it to the service and maintenance company, the factory might want to take some of it onboard with their own maintenance staff. In that case, it would be important that he supplier was happy to train the client on their own system…
"However, it is essential that, before you commit to an installation in the first place, you are satisfied that, should you want to change the service and maintenance provider, you can do so without the original company vetoing it by refusing to supply details of the engineering software."
5 Don't regard a building controls system/BEMS as 'fit and forget': Mike Malina, director of consultancy Energy Solutions Associates, has written a book called "Delivering Sustainable Buildings" (bit.ly/1n1ldUW).
He believes continuous optimisation should be central to any controls strategy: "It means that the building is maximising energy efficiency in the long term and you are reducing the likelihood of faults going undetected through continuous performance assessment."
For Malina, monitoring is the first step: "At its simplest, this means simple status monitoring: Is the equipment running when it is supposed to? Is it off when it should be? Does it open/close appropriately?"
The next step is to gather information on energy use in the building. Malina again: "From this, it is possible to identify areas of energy waste, or to spot areas around the building where energy use is particularly high."
Finally, deeper analysis of building energy use can include a comparison of your energy use against industry benchmarks. Malina concludes: "At this point it can be useful to implement energy-saving strategies such as demand-driven ventilation or heating.
"You may also find that simply encouraging building occupants to think more about their energy use can lead to excellent results."
The three main types of control
There are, according to the Carbon Trust, essentially three types of control which can be brought together in various combinations:
- Controlling by time – time controls vary in complexity from simple 24-hour on/off timers, to sophisticated seven-day timers, which allow for control to be set for individual days of the week. Upgrading existing time controls to enable services to be switched on and off to better match daily and weekly requirements can result in substantial savings.
- Controlling by occupancy – building services can be altered to accommodate changing staff working times. For instance, intermittently occupied spaces will often have lights left on unnecessarily. These are areas that could be better served using controls that switch lights off when no one is around. Occupancy controls are generally used for quick response services like lighting and individual ventilation fans. They are rarely appropriate for slower response services like heating and cooling across a whole building.
- Controlling by condition – building services can be controlled by environmental conditions such as temperature (for heating, cooling and ventilation), day-lighting (for lighting and shading), humidity (for ventilation and air conditioning), and even carbon dioxide levels (for ventilation).
Priva UK Ltd
Siemens Automation & Drives
This material is protected by MA Business copyright
See Terms and Conditions.
One-off usage is permitted but bulk copying is not.
For multiple copies
contact the sales team.