Tighten up your energy act before pondering the benefits of a CHP system
Combined heat and power (CHP) has to be sized so its heat and power are used productively for at least 4,500 hours a year. But before you start to weigh up what type and size CHP system you might invest in, you need to exhaust all of the long-term opportunities to reduce energy consumption throughout the building.
Follow the money to get the best CHP solution
An early port of call should be the billing data or, better still, data from an energy management system. Inexplicable hikes in energy consumption or lack of change when you might expect to see it – say between winter and summer or day and night – show where energy might be being wasted.
A tour of the building is likely to reveal wasteful use of heating, lighting, office equipment, and warehouse equipment. The patterns of energy consumption vary, so a series of walk rounds at different times is recommended - particularly at lunchtime, at night and over weekends. It’s important to check at the times when energy use should be low.
Heating typically accounts for about half of the energy used in offices and it consumes a significant proportion of the energy used in other businesses. Many workplaces are overheated - adding typically 8% to energy bills for each 1°C of unnecessary temperature.
It is a good time to consider CHP when boilers are coming up for assessment, however, the energy demand may need to be revised. A poorly operated or maintained boiler could be adding 30 per cent to your overall energy costs.
Simultaneous heating and cooling of a space is commonplace and wastes a lot of money. Where there are heaters and air conditioning units operating in the same space, set a 5°C dead zone between the heating coming off and the cooling kicking in to avoid both services fighting each other.
Not all areas will need the same heating requirements so consider heating the building in zones. This allows the CHP system to be adjusted for each area.
Strike a light
Installing high efficiency lighting can can reduce the lighting power requirements by up to 80% if converting from incandescent type lamps whilst still delivering the same light output and effect. The two most common technologies utilised in lighting replacement schemes are high frequency fluorescent type luminaires or Light Emitting Diodes (LED’s).
Get a new motor
Variable speed drives fitted to motors can reduce the speed of a pump or fan to match demand. A reduction of just 20% can halve the motor’s running cost.
Motors are among a group of electrical equipment, including welding sets, induction heaters and fluorescent lights that produce significant reactive power, effectively opposing the useful power the device consumes. Power factor is the measure of this and it is not uncommon for industrial installations to operate at power factors of 0.7 where 1.0 is the ideal. A power factor of 0.95 is achievable through power factor correction.
Now that you know how to future-proof your CHP projects, discover how much money you could save by downloading your free eGuide: Calculating CHP: A guide to savings and operating costs
Topics: CHP / Cogeneration