INTERNATIONAL NEWS
INCORPORATING COLD CHAIN operation , the choice of the lubricant can vary depending on the type of compressor , the design of the system and , mostly , the kind of refrigerant .
Joseph A Karnaz presented his paper ‘ Evaluating Lubricants for Lower GWP Refrigerant Compressor Operation ’ at the 16th International Refrigeration and Air Conditioning Conference in Purdue . This paper evaluates five potential candidates as substitutes for R404A and the potential impact of lubricant chemistry . The refrigerants considered are three non-flammable HFO / HFCs ( R448A , R449A , R452A ), one slightly flammable HFO / HFC / CO 2 blend candidate ( R455A ), and one flammable HC candidate ( R290 ). Investigation is made on how these refrigerants interact with lubricants ( miscibility , solubility , system performance ) and if current marketed lubricants used with R-404A are still good candidates to use with these lower GWP candidates .
Polyolester ( POE ) lubricant currently used with R404A in compressor operation is found to be satisfactory for use with most of the refrigerants investigated and has no negative effect on performance . By using ISO 22 POE lubricant , the effectiveness of R290 when compared to R404A shows better efficiency (+ 11 %) but some capacity loss ( -10%), which could mainly be from thermodynamics , but
R290 high solubility levels could be playing a role .
Lubricants like mineral oils , which typically have been unacceptable for use with R-404A due to miscibility concerns , are also not miscible with the HFO / HFC refrigerants studied .
INVESTIGATION OF REFRIGERANT LEAKAGE IN COMMERCIAL REFRIGERATION An article from Christina Francis et al . presents the results of a project that investigated refrigerant leakage within two of the UK ’ s major supermarket chains . The authors remind that the growth in the commercial refrigeration subsector is of concern , since it is reported to have the highest CO 2 equivalent emissions for the whole refrigeration , AC , and heat pump ( RACHP ) industry , equivalent to 40 % of total annual refrigerant emissions , despite it being responsible for only 22 % of worldwide refrigerant consumption .
Annual leak rates can be an average of 11 % and up to 30 % in some cases . Leakage data from 1 464 maintenance records were analysed . The analysis categorised the type and location of each leak and the volume of refrigerant replaced during repair . Over 82 % of the recorded leaks were from R404A refrigeration systems , and mainly advantagemechanical . com consisted of pipe or joint failures or a leaking seal / gland / core located in the compressor pack and the high-pressure liquid line .
The authors recommend that the industry focuses on developing leak tight design , installation , and maintenance of pipework and valves for the components that most often develop faults to minimise refrigerant leakage .
Source : C . Francis ; G . Maidment ; G . Davies . February 2017 . An investigation of refrigerant leakage in commercial refrigeration , International Journal of Refrigeration , vol . 74 .
Leakage data from 1 464 maintenance records were analysed .
COLD-STORAGE FACILITY CONVERTED TO PROPANE IN COLOMBIA
Asocolflores , the association representing flower exporters in Colombia , has replaced an R22-based system with R290 in a 392m 2 cold-storage facility for flowers , located in the Savanna of Bogota . us . jll . com
Asocolflores has replaced an R22-based system with R290 in a 392m 2 cold-storage facility for flowers in Columbia .
The performance of the system was analysed and results showed that R290 provides 10 % less of cooling capacity , but increases the coefficient of performance ( COP ) and reduces energy consumption by at least 10 %. To address safety concerns such as system pressure and refrigerant flammability , Asocolflores put in place several measures . In particular , an analysis on flammability based on the EN 378:2008 safety standard for refrigeration systems and a basic risk assessment under EN 1127-1:2011 was achieved . Assuming a 10kg charge of R290 , the maximum concentration level would be 25g / m 3 . The high charge is acceptable because the room is only accessible to authorised staff . Finally , technicians were trained to safely handle hydrocarbons .