Commercial refrigerant industry is one of the biggest contributing factors toglobal warming according to a study by Mota-Babiloni et al. (2015). Studies have shown that emissions of fluorinated greenhouse gases' effect on global warming can increase from 1.3% (2004) to 7.9% (2050) if no change in behaviour is implemented in the industry (Francis et al., 2017). At present, the F-Gas Ordinance sets requirements for leakage warning systems and periodic leakage detection.The most common leak detection systems consist of sensors locatedoutside the cooling process and measure the amount of coolant in the air. However, there are limitations with sensors, including measuring leaks in engine rooms with high air circulation and that the sensors are unable to measure small leaks and mistake other contaminants for refrigerant leakage (Leonardsson, 2021).The purpose of this study is therefore to investigate where leakage occurs in a refrigerant process, howoperating data changes andto propose an alternative detection method for refrigerant leakage.Johnson Control has other technical solutions such as their Performance Index which compares a cooling process operation in practice compared to the theoretical performance that the unit should deliver. In their own test facility, however, it was discovered that a unit can lose up to 20% of its refrigerantmassbefore a clear reduction in COP was discovered(Thorén, 2021).To discover where the leakage in a cooling process occurs, a field study was conducted on a cruise ship docked in Barcelona. The first field study on leak detection was initially carried out by direct method, with the help of an electronic leak detector. The indirect methodwas also used to complement the direct method, this was doneby ocularly looking for oil stains on and around the cooling process. It showed that leakage almost always occurs on the high-pressure side of gaskets, couplingsand plugs. Similar discoveries were made inthe study byFrancis et al. (2017).The results also showed thatthemore connectionsthere are on a unit, such as plugs or service valves, the greater probability that leakage will occur. A solution to reduce leakage on units with many connections,such as supply systems, couldbe to adjustthe design of the systemsand simply remove plugs for connections that are no longer usedfor different reasons.A second field study was conducted on the same cruise ship to determine what operational data changesdue to refrigerant leakage. The unit was emptied into a service tank for two minutes while operating data was logged. After analysis of the results in 16 different operating data points, three of themwere selected for the alternative leak detection model, the DGS-model.Data for longer operating periods, approximately 5 months, with fault-free operation for the selected parameters Θoutin evaporator, expansion valve opening degree and suction   overheating were compared with the operating data from the leakage experiment in field study 2. Thesethree were selected from a total of 14measured operating datapoints. The simultaneous increase ofall three operating data points indicatesrefrigerant leakage. That fact is the major reason for the selection of the three operating data points.Aprobability calculationbased on the three data pointswas created to calculate the probability of thedata points being outside a given range. If the probability calculation says that the chance of the reported value is zero, it is indicated that there is a problem with the process, most likely a refrigerant leak.As a proposal for further work,our proposal is to carry out validation tests of the DGS model on units in operation and a more accurate experiment on refrigerant leakage with operational changes per removed mass.

Rapporten redovisar resultatet från energikartläggningen samt utredningen om kylsystemet som genomförts på glassgrossisten i Umeå. En övergripande studie av hela verksamheten med samtliga tekniska system har utförts. Grossisten ämnar minska sin klimatpåverkan som orsakas av energianvändning i fastigheten samt läckage av köldmedium från kylanläggning och fordonskylaggregat. Grossisten förbrukar frånsett bränsle till lastbilarna endast elenergi. Följande energiaspekter har framkommit som betydande för verksamheten:   Total energianvändning                            394 MWh Kylanläggning                                          258 MWh      (65% av total energianvändning) Kylaggregat lastbilar                                75   MWh      (19% av total energianvändning) Kylanläggningen utgör en stor del av grossistens totala energianvändning och måste efter beslut från EU:s f-gasförordning åtgärdas innan år 2020 då ett service- och underhållsförbud träder i kraft för det befintliga köldmediet.   Utredningen avser besvara hur man bäst tillmötesgår detta förbud, konvertera och ersätta köldmediet för fortsatt drift av den befintliga anläggningen eller investera i en ny klimatneutral kylanläggningstyp. Efter inspektion av kylsystemet samt genomförd studie om kylanläggningar och köldmedier rekommenderas att investera i en ny klimatneutral transkritisk koldioxidkylanläggning. En prisuppskattning är gjord och har uppskattats kosta mellan 1,3 – 1,5 mkr.   Transmission (värmeförluster genom klimatskal) och infiltration (ofrivillig ventilation) står för 50 % av den totalt avgivna energin. Avgiven värmeenergi via kylanläggningens kondensorfläktar på taket står för 18 % och lastbilarnas kylaggregat 19 %. Förslag på effektiviseringsåtgärder som framtagits efter energikartläggningen är följande: Installera en luftridå för att minska infiltrationsflöden i portöppning mellan frys- och varmlager. Installera timerstyrda motorvärmare på gårdsplanen. Tillsätta ett nytt ventilationsaggregat med roterande värmeväxlare Täta kring nödutgången på fryslagret Utförs alla effektiviseringsåtgärder beräknas en minskning av energianvändningen med 42 MWh, detta utgör 11% av grossistens totala energitillförsel.   I samband med en installation av en transkritisk koldioxidkylanläggning finns stora möjligheter att installera systemet så att den högtempererade kondensorvärmen kan tillvaratas för värmeåtervinning. Den heta gasvärmen kan förvärma tilluften i ventilationsaggregaten samt värma tappvarmvatten. Detta skulle bidra till att sänka det totala energibehovet ytterligare. / The report presents the results of the energy mapping and the investigation of the cooling system performed at the ice cream wholesaler GB Glass in Umeå. An overall study of the entire operation with all technical systems has been performed. GB glass aims to reduce its climate impact caused by energy consumption in the property as well as leakage of refrigerant from the cooling system and vehicle refrigeration equipment. Except fuel for trucks the wholesaler only consumes electricity. The following energy aspects have been identified as significant for the business:   Total energy use                                       394 MWh Cooling system plant                                258 MWh      (65% of total total energy use) Refrigeration trucks                                 75   MWh      (19% of total total energy use) The cooling system plant constitutes a major part of the wholesaler's total energy use and must be rectified due to a decision by the EU's F-Gas Regulation by 2020 when a service and maintenance prohibition carries out for the existing refrigerant. The investigation concerns how to best accommodate this prohibition, convert and replace the refrigerant for continued operation of the existing plant or invest in a new climate-neutral type. After inspection of the cooling system and completed study of cooling systems and refrigerants, it is recommended to invest in a new climate-neutral transcritical carbon dioxide plant. A price estimate has been made and has been estimated to cost between 1.3 - 1.5 million.  Transmission (thermal loss through climate scale) and infiltration (involuntary ventilation) accounts for 50% of the total energy delivered. Ceded heat energy by the cooling plants condenser fans on the roof accounts for 18% and the truck's cooling units 19%. Proposals for efficiency enhancements developed after the energy survey are as follows:  Install an air curtain to reduce infiltration flows in the doorway between freezing and storage Install timer-controlled engine heaters on the yard Add a new ventilation unit with rotary heat exchanger Seal around the emergency exit on the freezer Performing all efficiency measures is estimated to reduce energy consumption by 42 MWh, which represents 11% of the wholesaler's total energy supply. In connection with the installation of a transcritical carbon dioxide cooling system, there is a great opportunity to install the system so that the high temperature condenser heat can be used for heat recovery. The hot gas heater can preheat the supply air in the ventilation units as well as heating the tap water. This would help to further reduce the overall energy demand.

Arbetet baseras på en kylanläggning som installerats på ett biogas företag, som till en början var tänkt som ett pilotprojekt men som nu används fullt ut i anläggningen. Projektet var inte utvärderat eller dokumenterat och vilken effekt som överförs var obekant. Arbetets innebörd var att beräkna effekten samt dokumentera systemet i form av både beräkningar, ritning och eventuella effektiviserings områden. Beräkning gjordes via entalpi skillnaden som togs ut över involverade värmeväxlare, samt flödet som togs ut via en reglerventil med hjälp av ett mätinstrument. Ritning gjordes via programmet Visio utifrån anläggningens nuvarande konstruktion. Resultatet för kyleffekten som överfördes beräknades fram via flöde och entalpi, med resultatet 14,03kW över båda värmeväxlarna. Även beräkning på vad en potentiell förbättring av isolering i rörsystemet skulle kunna bidra med där utifrån beräkningarna skulle energibesparingen kunna fördubblas gentemot nuvarande. / The work is based on a cooling plant installed at a biogas company, which was initially intended as a pilot project but is now fully used in the plant. It is not evaluated or documented and how much power is transmitted is unknown. The meaning of the work is to find out the effect and document the system in the form of both calculations, drawing and any areas of efficiency. Calculation was made via enthalpy the difference that was taken out over the heat exchangers involved, as well as the flow that was taken out via a control valve with the help of a measuring instrument. Drawing was made via the Visio program based on the facility's current design. The result for the cooling power that was transferred was calculated via flow and enthalpy, where the result was 14.03 kW over both heat exchangers. Calculation of what a potential improvement of insulation of the pipe system could contribute, based on the calculations, the energy savings could be doubled compared to the current one.