Travis Lumpkin of Hussman presented a webinar on Tuesday, 25 March entitled 'Micro-Distributed Advanced Refrigeration Technology' in which he discussed why hydrocarbons should be considered for refrigeration in the US, the pros and cons of the use of hydrocarbons in stand alone units for the retail industry as well as user safety.
Throughout Europe, hydrocarbons have, in the last years, caught on as efficient and environmentally friendly refrigerants, but in the United States there is still some trepidation when it comes to making the switch.
Travis Lumpkin opened with a brief background on refrigeration history. He stated, “we almost have come full circle with the refrigerants we use, now we’re back to natural,” commenting that natural refrigerants were utilised in the early days of refrigeration and now with regulations around the globe pushing for the phase-down and out of ozone depleting gases, natural refrigerants are making a comeback.
Why use hydrocarbons?
Lumpkin went on to explain that hydrocarbons are largely in use throughout Europe, and there are some compelling reasons for them to catch on in the US. The Montreal Protocol, which the US has ratified, calls for the phase out of ozone depleting substances such as HFC refrigerants. Further, the Environmental Protection Agency Significant New Alternatives Policy (SNAP) permits use of specific hydrocarbons as acceptable substitutes for ozone depleting substances in household food refrigerators and freezers (R600a and a blended R441a) as well as retail food stand alone refrigerators and freezers (R290). Under the SNAP rulings, R290 may be used in new refrigerators and freezers for food retail, and the equipment must meet all requirements in UL 471 (retail use) and UL250 (household use).
Other significant factors in favour of hydrocarbons use are their low global warming potential, R290 has an ozone depletion potential of zero and a global warming potential of only three, as well as the operational, environmental and financial impacts of refrigerant leaks in standard HFC systems. Aside from being environmentally friendly, R290 it is also considered a nontoxic ASHRAE A3 refrigerant
Hydrocarbon use in micro-distributed systems
Micro-distributed systems using hydrocarbon propane as the refrigerant are essentially stand-alone units for use in the retail industry. The propane charge limit for these retail units is maximum 150 grams per circuit. R290 is a colourless and odourless when used as a refrigerant, as adding odorant reduces efficiency. The units are typically water-cooled. Important in these systems are design components such as intrinsically safe electrical components, sealed systems (no valves or access ports), red-marked pipes and hoses for easy identification, and leak detection.
Propane in micro-distributed systems has R22-like refrigeration capacity and efficiency. Furthermore, the simplicity of design allows ease of installation, service and maintenance as well as flexibility in store operations. Propane is appropriate in both medium and low temperature applications, and these stand-alone units are easily moved around and restated.
Using qualified technicians and following the manufacturers’ safety guidelines allows for safe use of hydrocarbons
Propane/air mixtures are flammable between 2 and 10% propane by volume, and because propane is heavier than air, it tends to pool in low areas if a leak does occur. Furthermore, unlike natural gas, propane has no colour or odour so without proper leak detection equipment, it is nearly impossible to sense if there is a leak. However, hydrocarbons only present a risk if there is a leak when specific circumstances occur:
With the use of qualified technicians and following the manufacturers’ safety guidelines, hydrocarbons impart relatively little risk. It is also possible to minimise the initial leak potential by having as few joints and valves possible and minimising potential ignition sources. In addition, using intrinsically safe electrical components together with proper grounding and isolation of any non-spark free components aids in this.
Travis Lumpkin opened with a brief background on refrigeration history. He stated, “we almost have come full circle with the refrigerants we use, now we’re back to natural,” commenting that natural refrigerants were utilised in the early days of refrigeration and now with regulations around the globe pushing for the phase-down and out of ozone depleting gases, natural refrigerants are making a comeback.
Why use hydrocarbons?
Lumpkin went on to explain that hydrocarbons are largely in use throughout Europe, and there are some compelling reasons for them to catch on in the US. The Montreal Protocol, which the US has ratified, calls for the phase out of ozone depleting substances such as HFC refrigerants. Further, the Environmental Protection Agency Significant New Alternatives Policy (SNAP) permits use of specific hydrocarbons as acceptable substitutes for ozone depleting substances in household food refrigerators and freezers (R600a and a blended R441a) as well as retail food stand alone refrigerators and freezers (R290). Under the SNAP rulings, R290 may be used in new refrigerators and freezers for food retail, and the equipment must meet all requirements in UL 471 (retail use) and UL250 (household use).
Other significant factors in favour of hydrocarbons use are their low global warming potential, R290 has an ozone depletion potential of zero and a global warming potential of only three, as well as the operational, environmental and financial impacts of refrigerant leaks in standard HFC systems. Aside from being environmentally friendly, R290 it is also considered a nontoxic ASHRAE A3 refrigerant
Hydrocarbon use in micro-distributed systems
Micro-distributed systems using hydrocarbon propane as the refrigerant are essentially stand-alone units for use in the retail industry. The propane charge limit for these retail units is maximum 150 grams per circuit. R290 is a colourless and odourless when used as a refrigerant, as adding odorant reduces efficiency. The units are typically water-cooled. Important in these systems are design components such as intrinsically safe electrical components, sealed systems (no valves or access ports), red-marked pipes and hoses for easy identification, and leak detection.
Propane in micro-distributed systems has R22-like refrigeration capacity and efficiency. Furthermore, the simplicity of design allows ease of installation, service and maintenance as well as flexibility in store operations. Propane is appropriate in both medium and low temperature applications, and these stand-alone units are easily moved around and restated.
Using qualified technicians and following the manufacturers’ safety guidelines allows for safe use of hydrocarbons
Propane/air mixtures are flammable between 2 and 10% propane by volume, and because propane is heavier than air, it tends to pool in low areas if a leak does occur. Furthermore, unlike natural gas, propane has no colour or odour so without proper leak detection equipment, it is nearly impossible to sense if there is a leak. However, hydrocarbons only present a risk if there is a leak when specific circumstances occur:
- Vapour in a closed system is not flammable until oxygen is present
- Air mixture is within the defined flammability level
- Ignition source is present.
With the use of qualified technicians and following the manufacturers’ safety guidelines, hydrocarbons impart relatively little risk. It is also possible to minimise the initial leak potential by having as few joints and valves possible and minimising potential ignition sources. In addition, using intrinsically safe electrical components together with proper grounding and isolation of any non-spark free components aids in this.
MORE INFORMATION
By Elke Milner
Mar 27, 2014, 12:25
Related stories
PARTNERS
Sign up to our Newsletter
Fill in the details below
