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I think the future refrigerant for many applications is CO2, with a global warming potential of 1. Volkswagen put heat pumps with CO2 based refrigerant in thei

I think the future refrigerant for many applications is CO2, with a global warming potential of 1. Volkswagen put heat pumps with CO2 based refrigerant in their latest cars. Japanese company Sanden makes components for CO2 based heat pumps and compressors. https://www.sanden.co.jp/english/products/car/lineup/CO2-Compressors.html https://www.sanden.co.jp/english/products/car/lineup/CO2-Com... Project Drawdown estimates addressing the emissions of refrigerants to have one of the biggest impacts on climate change. https://www.drawdown.org/solutions/table-of-solutions https://www.drawdown.org/solutions/table-of-solutions

marcosdumay 4y ago
I wonder what is the advantage of those complex compounds (CFCs, HFCs, HFOs) when compared to CO2. EDIT: Well, duh, answering my questions after a quick search, CO2 liquefies in a much lower pressure than most gases.
- colechristensen 4y ago
  In short, the energy efficiency of moving heat depends on the working fluid.
- semi-extrinsic 4y ago
  Actually CO2 works very well, but you typically run it in a transcritical cycle where there is a gas cooler instead of a classical condenser unit.
  - marcosdumay 4y ago
    Or, in other words, for using CO2 efficiently on an environment-temperature heat pump, you need it to sustain higher pressures at both the hot and cool sides, and both the pump and nozzle to survive dealing with a higher density fluid that acts in many ways like a liquid. That explains why people keep searching for a different gas. What is interesting is that it's probably the best gas for that kind of cycle on environment-temperature, as it's too cold for water and amonia, but a low condensing pressure is a benefit here.
semi-extrinsic 4y ago
Yeah, natural refrigerants are the way - CO2, hydrocarbon gases, ammonia (in industrial settings), water/steam, and air - these can pretty much cover the entire temperature range that you will ever need in heat pumps. The natural refrigerants are indeed becoming increasingly popular. Essentially all new supermarket refrigeration systems in Europe are CO2-based nowadays, as an example. And almost all domestic fridges are using isobutane, freezers are using isopentane. Unfortunately there is a large push behind synthetic refrigerants, because there is a large industry who makes money off selling these compounds and would like to keep it that way.
- whatshisface 4y ago
  Do refrigeration engineers really fall prey to "big pushes" when everything they need to know about a gas is represented in those charts they use?
  - serf 4y ago
    kick-backs that produce inter-corporate relationships are vast and numerous. if X engineer is treated to a real nice dinner and game tickets by Company Y representative , very few charts will sway their opinion. tl;dr : most corporate products are not shaped purely by economic and efficiency metrics.
    - whatshisface 4y ago
      Yeah, both companies can easily do that, it doesn't change the balance.
    - eurasiantiger 4y ago
      That is corruption.
  - semi-extrinsic 4y ago
    In general you need to build the whole heat pump (incl. compressor) for the specific refrigerant and application you have in mind. So if you have an existing line of products using synthetic refrigerants, and a dozen factories around the world making those, you might very well choose to listen to a manufacturer of synthetic refrigerants pushing a new fancy one, rather than decide you need to re-engineer all your products for natural working fluids.

marcosdumay 4y ago

I wonder what is the advantage of those complex compounds (CFCs, HFCs, HFOs) when compared to CO2. EDIT: Well, duh, answering my questions after a quick search, CO2 liquefies in a much lower pressure than most gases.

colechristensen 4y ago
In short, the energy efficiency of moving heat depends on the working fluid.
semi-extrinsic 4y ago
Actually CO2 works very well, but you typically run it in a transcritical cycle where there is a gas cooler instead of a classical condenser unit.
- marcosdumay 4y ago
  Or, in other words, for using CO2 efficiently on an environment-temperature heat pump, you need it to sustain higher pressures at both the hot and cool sides, and both the pump and nozzle to survive dealing with a higher density fluid that acts in many ways like a liquid. That explains why people keep searching for a different gas. What is interesting is that it's probably the best gas for that kind of cycle on environment-temperature, as it's too cold for water and amonia, but a low condensing pressure is a benefit here.

semi-extrinsic 4y ago

Yeah, natural refrigerants are the way - CO2, hydrocarbon gases, ammonia (in industrial settings), water/steam, and air - these can pretty much cover the entire temperature range that you will ever need in heat pumps. The natural refrigerants are indeed becoming increasingly popular. Essentially all new supermarket refrigeration systems in Europe are CO2-based nowadays, as an example. And almost all domestic fridges are using isobutane, freezers are using isopentane. Unfortunately there is a large push behind synthetic refrigerants, because there is a large industry who makes money off selling these compounds and would like to keep it that way.

whatshisface 4y ago
Do refrigeration engineers really fall prey to "big pushes" when everything they need to know about a gas is represented in those charts they use?
- serf 4y ago
  kick-backs that produce inter-corporate relationships are vast and numerous. if X engineer is treated to a real nice dinner and game tickets by Company Y representative , very few charts will sway their opinion. tl;dr : most corporate products are not shaped purely by economic and efficiency metrics.
  - whatshisface 4y ago
    Yeah, both companies can easily do that, it doesn't change the balance.
  - eurasiantiger 4y ago
    That is corruption.
- semi-extrinsic 4y ago
  In general you need to build the whole heat pump (incl. compressor) for the specific refrigerant and application you have in mind. So if you have an existing line of products using synthetic refrigerants, and a dozen factories around the world making those, you might very well choose to listen to a manufacturer of synthetic refrigerants pushing a new fancy one, rather than decide you need to re-engineer all your products for natural working fluids.