Cost Comparison of a VPF Chiller and a Normal Chiller
Cost Comparison of a VPF Chiller and a Normal Chiller
(OP)
I would like to know the difference in the cost of a chiller suitable for variable primary flow system and a normal chiller for commercial chilled water system. According to the local Trane representative, there is no difference in the price of a two chiller types but other says there is a 15 % to 20 % difference in the chiller cost.
Please advice.
Please advice.





RE: Cost Comparison of a VPF Chiller and a Normal Chiller
However, working with mechanical engineers and Trane/York/Carrier reps, we have converted existing plants that have constant-flow primary - variable flow secondary to all-primary variable flow. No problems, and existing chillers were used.
Best to you,
Goober Dave
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RE: Cost Comparison of a VPF Chiller and a Normal Chiller
if hte chiller was designed with variable flow in mind, there is no cost difference
RE: Cost Comparison of a VPF Chiller and a Normal Chiller
RE: Cost Comparison of a VPF Chiller and a Normal Chiller
I am in the final stage of my thesis where I have to perform economic analysis of three different chilled water pumping schemes. I have already completed energy analysis with Carrier HAP. Three types of chilled water system configurations will be modeled in a typical application. The performance of conventional systems (constant-flow-primary-only and constant-flow –primary / variable-flow-secondary systems) will be compared with sustainable systems (variable-primary-flow system). The following performance factors shall be evaluated and compared with each other to quantify the energy and economic advantages of sustainable systems over conventional systems.
• Energy consumption
• Energy cost
• Life-cycle cost
• Simple payback period
Now if the cost of a VPF chiller is 15% to 20% higher than a normal chiller, there won't be any considerable difference in the life cycle cost as chiller is the most expensive equipment among all. So accurate information about chiller price is very important.
RE: Cost Comparison of a VPF Chiller and a Normal Chiller
some effort is always needed to swim through ocean of commercial talks and get right technical information.
RE: Cost Comparison of a VPF Chiller and a Normal Chiller
I don't know every device availabe, my statement is just based on the ones I deal with, but for those there isn't n option. My experience very small devices (i.e. boilers under 750,000 btu/h) are designed for primary/secondary flow (you can do varaiable primary, but it gets complicated), the larger devices are for variable primary flow by design and not as an option.
You also save on pump, piping, wiring and space by not having primary pumps. and unless you lead/lag each primary pump, overall pump reliability will be higher with variable primary flow.
RE: Cost Comparison of a VPF Chiller and a Normal Chiller
RE: Cost Comparison of a VPF Chiller and a Normal Chiller
Largest differences were for pump sizing, minimizing size of distributed booster pumps, and added costs for pump bypasses (existing system was a constant primary/constant secondary of 1970's design), additional dP's, and higher cost of pressure independent control valves.
It would also depend on your central plant configuration and chiller sizing. With LCCA and full bin data, a smaller chiller with VFD and two larger chillers with IGV were selected. Still tuning the booster pumps and dP's. Had a hiccup with controls so also still tuning optimization with condenser water, might just give up and buy a loop optimization program like Hartman's.