Cooling & refrigeration
Apply passive techniques to avoid/reduce air conditioning demand
- night cooling to avoid installation of air-conditioning in mechanically or naturally ventilated buildings (10 - section 3.3)
- night cooling to reduce daytime cooling loads in air conditioned buildings (10 - section 3.3)
Specify efficient cooling/refrigeration equipment
- specify refrigeration equipment with high efficiency (high CoP) ()
- follow guidelines of typical and good practice performance indicators for conventional systems as shown in CIBSE Guide F Section 8 Tables 8.1 and 8.2 (7 - table 8.1 8.2, 11)
- refrigeration equipment with high coefficient of system performance (COSP) as this takes into account the power used by all compressors and auxiliary plant ass well (7 - section 08/03/01)
- efficient components - condensers, evaporators, expansion valves, compressors, pumps and fans (7 - section 08/04/01)
- compressors optiomised to increase the proportion of time they operate at full load (7 - section 8.6)
- condensing temperatures low and head pressure control avoided (7 - section 8.6)
- higher evaporating temperatures (7 - section 8.6)
- rapid cycling of unloading mechanisms avoided (7 - section 8.6)
- auxiliaries can be controlled effectively at low loads (7 - section 8.6)
Apply 'free' cooling techniques to reduce air conditioning demand
- free cooling systems (especially where the cooling demands are high and unrelated to ambient temperature, for example in computer suites and telephone exchanges) (7 - section 08/01/03, 1 - section 3)
- load shaving to combine free and mechanical cooling when ambient conditions are favourable (1 - section 2.2)
Raise supply temperatures when possible
- larger, more efficient heat exchangers for cooling air (7 - section 08/01/02)
- increased chilled water or supply air volume flow rates (with increased pipe and duct sizes to maintain the same pump or fan power) (7 - section 08/01/02)
- increased chilled water flows through heat exchangers (with increased pipe sizes to avoid increasing pumping energy e.g. using chilled ceilings) (7 - section 08/01/02)
- cooling duties that require low temperatures separated from more general cooling duties that can be achieved with higher temperatures (7 - section 08/01/02)
- higher set points at times of lower cooling demand (7 - section 08/01/02)
Design the building structure and fit-out to optimise available thermal mass
- thermal mass in the structure available to reduce diurnal indoor temperature range (by storing daytime heat, usually to be purged via night cooling) (7 - section 4.2, 12 - page 7)
Consider efficient equipment
- feasibility study of thermal storage (7 - section 08/03/01, 2)
- heat recovery where this is effective (7 - section 08/02/02)
Minimise internal heat gains from lighting and equipment
- office equipment with lower power use (Average heat emissions from equipment as given in CIBSE Guide F Section 12 Table 12.5 & 12.6) (7 - table 12.5, 12.6, 13 - section 6.5)
- improved power management controls (e.g. turning off lights and personal computers when not in use) (7 - section 08/01/01)
Design good HVAC controls
- optimised set points (e.g. space temperature, air supply temperature, recirculation rate and humidity) (7 - section 08/01/01)
- improved, but not necessarily closer, control of temperatures, flows and humidity (7 - section 08/01/01)
Design good controls
- chillers and chilled water systems only operate when there is a real cooling demand (7 - section 8.6, 5 - section 5)
Size plant correctly (i.e. avoid oversized plant)
- cooling (refrigeration) plant sized correctly (i.e. avoiding oversizing) (3 - section 7, 7 - section 7)
- DHW boiler plant sized correctly (i.e. avoiding oversizing) (7 - section 7)
- pumping plant sized correctly (i.e. avoiding oversizing) (3 - section 7, 7 - section 7)
- air handling fan plant sized correctly (i.e. avoiding oversizing) (7 - section 7)
- main space heating boiler plant sized correctly (i.e. avoiding oversizing) (7 - section 7)
- chillers are suitably sized as oversized plant can lead to inefficiency (9)
- air handling unit fans are suitably sized as oversized plant can lead to inefficiency (9)
Reduce solar gains by the appropriate design of the building envelope, glazing, and shading
- shading devices on windows to reduce excessive solar gains (7 - section 4, 4 - section 3, 12 - page 7, 8, 4, 8, 4)
- external walls with a light finish that reflects more potential solar gains (14)
Reference Documents
| Series Number | Publisher | Title | |
|---|---|---|---|
| 1 | BG 8/2004 | BSRIA | Free Cooling Systems |
| 2 | TM18 | CIBSE | Ice Storage |
| 3 | GN 13/97 | BSRIA | Oversized cooling and pumping plant - a guide to reduce the energy consumption of oversized cooling or pumping plant |
| 4 | BR364 | BRE | Solar shading of buildings |
| 5 | Guide H | CIBSE | Building control systems |
| 6 | Carbon Trust | Focus - the manager's guide to reducing energy bills | |
| 7 | Guide F | CIBSE | Energy efficiency in buildings |
| 8 | TM37 | CIBSE | Design for improved solar shading control |
| 9 | Carbon Trust | Managing Energy Use - minimising running costs of office equiptment and related air-conditioning | |
| 10 | KS3 | CIBSE | Sustainable low energy cooling an overview |
| 11 | GIR 85 | Carbon Trust | New ways of cooling |
| 12 | GBG 63 | BRE | Climate change impact on building design and construction |
| 13 | Guide A | CIBSE | Environmental design |
| 14 | Carbon Trust | Environmentally smart buildings - a quanity surveyors guide to the cost effectiveness of energy efficiency in offices |