A simple relative investment cost structure for the refrigeration equipment, compressors, condensers and installation has been built up on the following basis:
Cooling cabinets are not included.
Within this framework user input cost baseline case is shown and the values for comparison cases are adjusted according to the following weightings:
These charts show the “adders” applicable in each case. So, for example, under compressor type, we have a 20% applied cost adder for a semi-hermetic reciprocating compressor to be comparable with a scroll with the same refrigerant. There is no cost adder for most refrigerants although there is a penalty for R134a and HFO (70% more displacement required) and for R744 (high pressure technology). System type also affects the compressor investment. More cooling capacity redundancy is needed for distributed systems and the cascade and booster systems require more displacement as the LT vapour is handled twice.
- A semi-hermetic reciprocating compressor with R134a will have an adder of 20% (type) plus 20% (refrigerant) giving a total adder of 40% to the baseline scroll R404A.
- A booster system using R744 will have a cost adder of 20% (type) plus 20% (refrigerant) plus 40% (system) giving a total adder of 80%. The assumption is made for R744-transcritical compressors out of large volume production. Today's cost/prices may still be significantly higher.
Additional volume flow rate of R134a and HFO is the reason for a 20% additional cost with an 80% adder also applied to R744 components. DX distributed systems have more cost built into the pack, but require less site assembly, and this is reflected below. Cascade and booster systems have additional circuits, controls and heat exchangers
A 30% cost adder has been included for the R744 gas cooler, receiver/separator and additional controls.
The refrigerant element is only 5% of the total installation cost so the weightings have little effect except in the case of HFO where a very high cost is involved. There is a degree of uncertainty about the eventual HFO cost, and a factor of 5 times R404A has been applied in absence of specific information from refrigerant manufacturers.