13 Minimise wasteful plant operation, ensure local public holidays are scheduled, specify optimum start and stop, limit after hours operation to no more than one hour per request.
6.11
14 Ensure adequate motorised branch duct dampers are installed to prevent after hours HVAC operation in un-occupied zones.
6.4
15 Ensure adequate sub metering is installed in line with Green Star requirements, NABERS requirements and for monitoring KPIs. Ensure meters are connected to BMS, the readings are recorded, trended and archived. To assist the Facilities Managers, consider specifying trend analysis software and exception reports.
2.4.3, 2.5.3.
Task Action Section in Guide
16 Specify diagnostic screens to enable tracing of faults. Screens should be set up for chilled water system, condenser water system, hot water system, and for each AHU including the VAV boxes it serves. Screens should display key information including heating/cooling calls, equipment staging and key control parameters and control logic.
6.11
17 Specify control interfaces to Tenant installed equipment to ensure that these systems cannot counteract the central systems.
6.9, 6.11
18 For the control of fan coils, use room sensors instead of return air sensors. 6.9, 6.11
19 Specify adequate sensors for performance monitoring of HVAC systems. Include airfi lter differential pressure, pressure and temperature drops across chiller condensers and evaporators. The installation of sensors after heating and cooling coils can also detect leaking valves and energy wastage.
6.11
20 Don’t over-specify tight temperature control bands. Specify 1–1.5ºC dead zone between heating ‘off’ and cooling ‘on’ in occupied areas.
6.11
21 Don’t over-specify tight temperature control bands for areas such as entrance lobbies used for transient occupancy. Typically, the temperature within such areas can be allowed to ‘fl oat’ between 17ºC and 27º without complaints and adverse effects to occupied areas.
6.11
22 Specify correct installation of sensors and their calibration. Where sensors are mounted on external cavity walls, ensure gland seals are installed to prevent air leakage into sensor enclosures and thermal insulation is applied behind the sensor.
6.11
Chiller
23 Specify chillers that have high COPs and IPLVs, in accordance with the expected duty cycles.
6.2
24 Apply whole of life costing – consider water cooled, adiabatic and air cooled options. 6.2, 5
25 Consider variable volume chilled water pumping, including the possibility of usingchillers in series-counter fl ow confi guration.
6.2
26 Consider chilled water re-set and condenser water reset. 6.2
27 Ensure that chillers are sequenced correctly to deliver the most effi cient output for the prevailing chiller demand. Stage chillers up/down based on current (A) draw of compressors rather than kWr.
6.2
28 Minimise spurious cooling demand calls – specify an ambient low temperature lock-out and give consideration to cooling calls – avoid the possibility of a faulty motorised valve or broken VAV box causing a cooling call.
6.2, 6.11
29 Specify electricity sub-metering and chiller thermal metering to enable monitoring chiller performance and KPIs.
2.5.3
30 Specify high level interface with BMS. 6.2, 6.11
Boiler
31 Specify boilers that have high effi ciencies. Use condensing boilers as the lead boiler where appropriate.
6.5
32 Minimise heating calls – specify an ambient high temperature lock-out and give consideration to verifying heating calls – avoid the possibility of a faulty motorised valve or broken VAV box causing a heating call.
6.5, 6.11
H Ap p e n d ix H : C h e c k li s t – D e s ig n E n g in e e rTask Action Section in Guide
Cooling Tower
33 Optimise selection, combine base building and Tenants supplementary cooling towers together to obtain the lowest approach temperature possible with minimum consumption of fan power.
6.3
34 Specify a fan sequencing strategy that simultaneously operates all fans in parallel, rather than ramping individual fans to 100% before staging the next fan.
6.3
35 Specify wet bulb tracking system that uses at least two ambient dry bulb/wet bulb sensors.
6.3, 6.11
36 Install water metering connected to BMS. Set up KPIs and alarm functions to report abnormally high and low water consumption.
6.3, 6.11
37 Install automatic bleed through a TDS system. Monitor the system through BMS. 6.3, 6.11
AHU
38 Specify low pressure drops on the air and water side. 6.4
39 Oversize heat exchangers where appropriate, to get the most effi ciency from chillers (higher chilled water temperatures) and boilers (lower heating water temperatures using condensing boilers) where feasible.
6.4
40 When considering zoning, take into account orientation, variances in heat loads and after-hours plant requests.
6.4
41 Minimise the need for active de-humidifi cation and humidifi cation. 6.4,6.8
42 Use the economy cycle to maximum potential, in humid areas sense enthalpy of air rather than dry bulb temperature. Use two enthalpy sensors to check for sensors drifting out of calibration.
6.4
43 Control outside air based on CO2 sensing, especially important for variable occupancy areas.
6.4
44 Specify critical zone re-set for the control of AHU fans rather than using a fi xed static pressure.
6.4
45 Avoid using hi/low select signal from zone sensors for AHU control zone purposes, the hi/low select signal could be originating from a zone served by a faulty VAV box. Use a verifi cation system or an averaging system to reduce the possibility of a faulty VAV box affecting the operation of the entire AHU.
6.4
46 Use night purge when suitable outdoor conditions exist, use enthalpy sensing in humid climates. Excessive use of night purge (>2 hours) can be counterproductive. Disable heating system for a set period (e.g. 2 hours) after night purge ceases.