Hot Water Heat Pumps & Refrigerants
Heat Pumps & Refrigerants
What heat pump solution to consider.
Heat Pumps & Refrigerants selection is key to successful relationship of desired project temperatures and efficient outcomes. For hot water there are many uses. From Showers to Air-Conditioners. However the nature of the hot water system comes down often to demand and temperature ranges required. Understanding the differences for hot water heat pumps & different refrigerants and their properties will help you select the right system for you.
If water is being kept in storage for hot water systems, it must be kept at a temperature of at least 60 Celsius to avoid bacteria growth. However, after years of scolded children temperatures of less than 49 Celsius at the tap are advised. However, if it is just for a circulation loop then lower temperatures can be used. To understand the right system, you first need to know where your temperature needs are.
Limitations of Heat Pumps & Refrigerants
The limitations of heat pumps as a hot water choice is that refrigerants have a burn point. A temperature that once reached will burn the refrigerant and make the heat pump useless till the unit has been fixed and the refrigerant replaced.
Critical or absolute maximum operating temperature and normal operating temperature pressure give you a good ideal uses of the refrigerants.
So what are these limitations.
| Refrigerant | Critical Temp | Temp at 300 PSI |
| R22 (Now obsolete) | 96.14 | 54.73 |
| R134A | 101.1 | 71.11 |
| R404A | 72.12 | 47.54 |
| R407C | 86.19 | 53.21 |
| R410A | 71.34 | 35.58 |
These operation temperatures you can see that R404A & R410A are low temp refrigerants and great for air-conditioners or chillers due to their lower operating temperatures. R22 (Now obsolete) and R 407C are ideal for heat pumps for swimming pools and R 134A is better suited to hot water solutions.
The other issue with refrigerants is their capacity in kW at those temperatures. So while R134A is better suited for a hot water system, it has a much lower kW output capacity when compared to R407C. This significance of this is for the same capacity ratting you need a far larger heat pump to achieve the same amount of work.
An 8 HP R407C heat pump will give you 37 kW of heating as compared to requiring a 12 HP R134A heat pump.
So if you do not require 60 Celsius or more, you are better using a system based on R407C. This will save you a lot of cost in the equipment side of things.
Data based on Nominal Ratings @ 15oC Evaporating Temp & 50C Condensing
| Compressor HP | R407C kW | R134A kW |
| 3 | 15.59 | 10.10 |
| 4 | 18.93 | 12.13 |
| 5 | 23.73 | 15.39 |
| 6 | 28.25 | 18.21 |
| 8 | 37.37 | 23.28 |
| 10 | 48.43 | 30.46 |
| 12 | 55.3 | 34.79 |
What Does this All Mean?
When you are investigating heat pumps as an energy efficient alternative to a Gas based boiler, you need to take into account the hot water range you actually require.
For medium hot water 43 Celsius to 55 Celsius, then select a R407C system. But if you do require that little extra temperature then the right choice would be to select a R134A refrigerant based system.
What does Toyesi Offer?
Here at Toyesi we can now provide hot water systems for commercial applications.
- Air to Water systems
- Water to Water Systems (i.e off a cooling tower)
- Multi Function systems. (I.e heat your pool and provide hot water all in 1 system)
- R407C & R134A refrigerant systems.
- Installation options – Outdoors or Plant room solutions.
- Single walled and Double Walled heat exchangers
- All custom designed and built for your project.
