New Equipment for Old Plant Rooms

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Alfred Jenkins
7 years ago
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1 Agenda New Equipment for Old Plant Rooms Peter Logovik Mechanical Engineer Ashburner Francis 1. VRF 2. Heat Exchanger 3. Desiccant Pre conditioners 4. New Chiller application 5. Pumps Inline vs. traditional 6. EC Fans vs. centrifugal type + design tips

2 High Rise Whole Floor Plant Room Were often larger than needed to be for Future Expansion On floor Plant Rooms Typically split contains all services including: large central air handling units Chillers Boilers Pumps Central domestic hot water systems Switch room Generators Miscellaneous ventilation fans Fire essential services (smoke exhaust/stairwell pressurisation) Large supply air duct work droppers feed on floor system Central return air system with sub ducts Central toilet exhaust system Central tenant fresh air dropper Central condenser water system On floor ceiling space typically >600mm Economy cycle Dampers Western Perimeter Male Toilet FCU Stair 1 Meeting room Lunch room FCU Plant Room Central Zone Southern Zone Lift Shaft Hallway Stair 2 Female Toilet Eastern Perimeter

3 What is VRF/VRV? Variable Refrigerant Volume/Flow Heat Pump heating only OR cooling only Heat Recovery Simultaneous heat & cool New domestic hot water heating capability Side discharge condensers available VRF Heat Pump System

4 VRF Heat Recovery System VRF Condenser Side Discharge systems

5 VRF Hot/Cold Water Production De centralised on floor heating/chilling solution Utilized small bore DX pipe work to get to floor, then provide local water circulation loop Integrate with hydraulic trades to reduce domestic water heating costs. Where? Whole or part retrofit buildings Spaces with varying uses, operational hours orientation To unload existing chilled/condenser water systems Reducing central CHW capacity Lowering flow rates through existing pipe work Allow the chiller to operate more efficiently

6 Capacity [kw] Footprint VRF Space required 1 AC 2 AC 3 AC 1 WC 2 WC 3 WC x 830x x 4160x x 6240x x 550x x 1300x x 2050x 1160 Area [m^2] Airflow [L/s] Weight Why Use VRF/VRV? Great compromise between individual split systems & large central chiller type air conditioning systems Saves outdoor space Increased efficiency at low/part load Better individual space temperature control More flexibility in designs Modular design Reduced maintenance cost Unload existing system Provide on floor DX or water source heating

7 Western Perimeter Male Toilet VRF HP FCU VRF for On floor Plant Rooms FCU Stair 1 Meeting room Lunch room FCU Plant Room Central Zone Lift Shaft Hallway Stair 2 Female Toilet VRF HP FCU Eastern Perimeter What is HRV/ERV? Heat/Energy Recovery Ventilator Energy is exchanged between two air streams Stale room air is exhausted past fresh outside air Southern Zone

8 Inside Heat Recovery Ventilators Where Would You Use HRV/ERV? Best bang for your buck : Where fresh air content are >40% of total SA Where spaces operate 24/7 High occupancy areas To unload existing mechanical infrastructure to accommodate expansion of services.

9 Western Perimeter HRV unloading for On floor Plant Rooms Male Toilet FCU Stair 1 Meeting room Lunch room FCU Plant Room Central Zone Lift Shaft Hallway Stair 2 Female Toilet Eastern Perimeter Why Use HRV/ERV? Reduces air conditioning operating costs Allows greater quantities of fresh air delivered to spaces without additional power usage Allows smaller air conditioning systems to be installed reducing initial procurement costs and plant space Assists existing air conditioning systems to cope under peak loads where they might be struggling Southern Zone

10 Example of HRV Cost Effectiveness Straight DX Package, 134kW, 6000L/s ductwork duct work c/w economy cycle. Total job cost approximately $48,900 Heat Recovery Package unit, 70kW, 3000L/s duct work c/w economy cycle. Total job cost approximately $51,000 DX Package size 4355 long x 2420 wide x 2405 high Air Change Package size 2350 long x 2700 wide x 1865 high DX Desiccant Wheel Heat Recovery Package Unit Example

11 What is a Desiccant Unit? DX or CHW/HW Desiccant Wheel Air Processing Package Unit

12 Where Would You Use a Desiccant Unit? Reduce energy costs associated with outdoor air cooling for: high humidity climates high occupancy density areas Libraries, hospitals, art galleries & laboratories Why Use a Desiccant Unit? Reduces fresh air treatment energy consumption therefore reduce operating costs Reduces mold growth in duct work and conditioned spaces Reduces the kw capacity of AC plant offsetting initial procurement cost. Allows space neutral air to be provided in fresh air supply duct.

13 What is a Heat Recovery Chiller? Traditional chillers Produces chilled water rejecting energy to the atmosphere Heat Recovery Chiller Heating processes traditionally via boilers electrical duct heater heat pump air conditioning systems Heat Recovery Chillers Produces chilled water OR chilled water & hot water Heat Pump/Recovery Chillers Varying amounts of chilled water and hot water simultaneously increasing flexibility

14 Heat Pump/Recovery Chiller Heat Pump/Recovery Chiller Gas for use in Boiler Heating Cost Comparison for 512kW of heating for 1Hr Electrical for duct heater bank Electrical for Electrical for HP/HR Heat Pump Chiller $ $ $ $ 2.12 HP/HR Chiller takes only an additional ~ 10.6kW extra to develop 512kW of heating

15 Why Use a Dual Purpose Chiller? No need for two pieces of equipment (chiller + boiler, heat pump & electric reheat) Reclaims waste energy saving operational running costs Reduces plant space requirement & infrastructure Reduces maintenance cost Low load application HVAC Pumps Inline vs. End Suction Pros Flexibility Cheap heating Plant room space saving Integrate with domestic hot water & OA pre treatment Cons Small T Only low grade heat Large water flows

16 Pump Cost Example Fan Arrangement Pump Example: duty 165Pa (1.5kW motor) Long Couple Pump $ VSD + wiring cost Long Couple Pump $3445 (integrated VSD) Close Couple Pump $4975 (integrated VSD) Consider using inline pumps in tight plant rooms Tertiary pump may be wall mounted Consider using combined Motor/VSD packages to save plant room wall space and messy wiring.

17 Fans Type Comparison EC Plug Fan Rule of thumb EC Fans vs. Centrifugal Example: 4400L/s fan at 1000Pa (large exhaust application) Type Width [mm] Length [mm] Height [mm] Motor [kw] Abs Power [kw] Weight [kg] Cost SISW Centrif EC Plug DIDW Centrif * Note: 1) Suggested plug fan enclosure size for plug fan is 1154 wide x 1154 high x (1.33sqm) 2) If used on cooling coil application, fan box size can service 2.5m/s 3) Pressure performances are similar, however, plug fans are quicker to spin up and slow down 4) Centrifugal fan price excludes VSD cost, however, the plug fan price excludes the cost of the casing 5) EC Plug fan has better part load performance 6) Centrifugal fan absorbed energy excludes VSD and wiring losses. 7) EC plug fan can be controlled via 0 10V AI from a BMS Square discharge box 2 x diameters (D) of the fan Length of discharge box shall be 1xD from the discharge face of the wheel OR ~ 1.5xD from the suction inlet. ⅟2xD radius clear on suction side to obstruction. Currently largest plug fan is ø900 limited to 350Pa Retrofitting Use multiple plug fans to replace larger DIDW fans by the super position technique

18 If you use it, don t waste it If you just used it, recycle it Thank You

HVAC Systems: Overview

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