Post on 21-Aug-2018
AIA Quality Assurance
The Building Commissioning Association is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reported to AIA/CES for AIA members. Certificates of the Completion for both AIA members and non-AIA members are available upon request.
This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product.
Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
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Learning Objectives
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1. Identify basic design criteria for a VRV/VRF central plant alternative.
2. List common installation issues for VRV/VRF and variable speed heat pump systems.
3. Assess plant efficiency for performance monitoring programs. 4. Compare the criteria for selecting a system for a VRV/VRF vs.
a traditional central chilled water plant.
Types• Air Cooled • Water Cooled • Absorption
Optimization illustrations and strategies• Design Considerations
• Sizing• Layout• Type• Operational Considerations• Setpoints• Staging
Central Chilled Water Plants
Central Chilled Water PlantsThe newer studies1,2 validated an older American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) study showingthat there was about an 8 percent U-Value loss after 4 to 5 years of operation. Important takeaways from these studies include:1.With oil typically found in chillers, properties that promote miscibility necessary to lubrication lead to reductions in heat transfer rates in the heat exchangers.2.Oil concentrations above 0.5 percent cause reductions in bubble size formation at the tube surface, which reduces heat transfer rates.3.The effect was highest between 1.3 percent and 3.5 percent. The negative effect increased in a linear fashion according with the oil percentage above 0.5 percent.
Central Chilled Water Plants
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0 20 40 60 80 100 120
Effic
ienc
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/ Ton
% Load
Effects of Part Load and Condesner Water Temperature on Chiller Efficiency
82 80 75 70 65 60 55 50 45 36
Central Hot Water PlantsTypes
• Hot Water – Condensing Non-Condensing
• Steam
• High Temp Hot Water
Optimization illustrations and strategies• Design Considerations
• Sizing
• Type