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VRV Combination Ratio or Connection Ratio? 1
- Thread starter tomVDV
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1
- #3
Different manufacturers have slightly different terms, but that is about the mentioned principle.
Your outdoor unit has nominal and maximal rating, while indoor units have something like maximum capacity they can have under certain conditions.
Sum of indoor units maximum ratings divided to outdoor unit maximum rating gives your connection ratio.
You have to remember that it does not mean you can reach sum of indoor maximums, it is only allowed conneciting. Maximum is defined by outdoor maximum.
This reflects reality of coincident loads. If you calculate coincident maximal load for system in your calculations, and maximums for all romms, difference will be large the larger number of rooms and the more different orientation.
What does this all means? It means you can save money by specifying outdoor unit on maximum coincident load, not on sum of indoor maximums, taking care that connection ratio is not exceeded.
Your outdoor unit has nominal and maximal rating, while indoor units have something like maximum capacity they can have under certain conditions.
Sum of indoor units maximum ratings divided to outdoor unit maximum rating gives your connection ratio.
You have to remember that it does not mean you can reach sum of indoor maximums, it is only allowed conneciting. Maximum is defined by outdoor maximum.
This reflects reality of coincident loads. If you calculate coincident maximal load for system in your calculations, and maximums for all romms, difference will be large the larger number of rooms and the more different orientation.
What does this all means? It means you can save money by specifying outdoor unit on maximum coincident load, not on sum of indoor maximums, taking care that connection ratio is not exceeded.
AnotherEllis
Mechanical
This is the biggest fight I have had on VRV/VRF systems. A design zoned to take advantage of diversity can get well in excess of 130% FC:CU ratio.
Daikin and Sanyo understand this. LG does not. It is maddening.
Daikin and Sanyo understand this. LG does not. It is maddening.
130% is the usual maximum connection ratio for most systems. Some of them allow up to 200 % ratio (Daikin, Mitsubishi) only you have to work with a manufacturer's rep. They can submit your application to the manufacturer's engineering department. For all applications exceeding 130% ratio, the o.k. is given on individual project basis.
AnotherEllis
Mechanical
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