| 1. |
- Haglund Stignor, Caroline, et al.
(författare)
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New type of energy efficient heat exchanger for indirectly cooled display cabinets - Laboratory and field tests
- 2018
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Ingår i: Refrigeration Science and Technology. - 9782362150241 ; , s. 206-214
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Konferensbidrag (refereegranskat)abstract
- In this study, a completely new type of air-to-liquid heat exchanger, adapted for obtaining good heat transfer performance even at a laminar flow regime on the liquid side has been evaluated in a display cabinet application. The heat exchanger consists of parallel plates, with liquid in every second passage and air in the other passages. Tests were performed with a traditional open vertical display cabinet, first with a traditional finned-tube coil and thereafter with the new type of heat exchanger, both in a climate chamber and thereafter in the field. The results from both tests showed that the liquid inlet temperature could be increased by around 6°C, from the range -8°C - -7°C with the traditional coil to the range -2°C -1°C with the new type of heat exchanger, which can lead to considerable energy savings and operation without the need for defrosting of the heat exchanger.
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| 2. |
- Jha, Piyush K., et al.
(författare)
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Freezewave H2020 project-microwaveassisted freezing of potato
- 2018
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Ingår i: Refrigeration Science and Technology. - 9782362150241 ; , s. 190-195
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Konferensbidrag (refereegranskat)abstract
- In the recent times, several novel freezing techniques have been attracting remarkable attention not only within the scientific community but also in the food industry due to their ability to enhance the formation of small size ice crystals and to prevent food products from freeze-damage. One of these is freezing assisted by electromagnetic waves. This short study was intended to investigate the impact freezing under low power microwaves (MWs) (2450 MHz) had on the freezing time and the microstructure of the potatoes. The time taken by the conventional freezing process to reach - 10°C from 6°C was 13.95 min, while the same temperature change was achieved within 37.53, 19.87 and 20.18 min for short pulse high power (SPHP), long pulse low power (LPLP) and constant microwave (MW) freezing conditions, respectively. Although that the application of MWs during freezing process, as it was expected, resulted in longer freezing time compared to conventional freezing condition, the image analysis (X-ray micro-computed tomography) results revealed that the application of MWs during freezing process produced better microstructure than the conventional method.
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| 3. |
- Le-Bail, A., et al.
(författare)
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Freezewave; A new European project on freezing under microwaves irradiation
- 2018
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Ingår i: Refrigeration Science and Technology. - 9782362150241 ; , s. 182-189
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Konferensbidrag (refereegranskat)abstract
- FREEZEWAVE project is an ERANET SUSFOOD project (May 2015 - Dec. 2018). It concerns the freezing of foods using a highly innovative technique combining freezing at slow rate with part time emission of microwaves (2450 MHz); this innovative concept has been investigated recently by ONIRIS and results showed that a 62% decrease of the average ice crystal size was acquired when samples were frozen under microwave irradiation compared to the control (Xanthakis et al., 2014, IFSET - study on pork meat). To improve the quality of frozen foods, fast freezing is usually recommended, resulting in a reduction of the ice crystals. However, a fast freezing increases the energy demand: low ambient temperature & high air velocity to enhance the rate of heat transfer are needed to achieve a fast freezing. FREEZEWAVE project aims at expanding & optimizing the concept to several foods (sauce, meat, vegetable & ready to eat meals) and also at designing industrial equipment. The novel concept concerns the freezing equipment sector thanks to a French SME partner (SAIREM) and the global frozen food sector. FREEZEWAVE will provide scientific knowledge and new scientific insights in food freezing. Project's outcomes may also be of interest for non-food applications such as biotechnology.
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| 4. |
- Le-Bail, Alain, et al.
(författare)
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Review on the impact of electrical and magnetic disturbances during freezing
- 2018
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Ingår i: Refrigeration Science and Technology. - 9782362150241 ; , s. 225-232
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Konferensbidrag (refereegranskat)abstract
- Phase change in biological tissues may be affected by electrical and magnetic disturbances. This presentation proposes a review based on existing literature as well as some very recent results on freezing under static electric field (SEF), magnetic field (MF) and electromagnetic radiations. Freezing under static electric field of water, aqueous solution and pork meat has been investigated by the authors, showing the ability of this process to refine ice crystals in frozen matrices. SEF permits to lower the supercooling and to trigger the phase change of water to ice. Radiofrequencies and microwaves havebeen used recently by researchers to promote refined ice crystallization in food systems. Even though the energy optimization of the process is still in debate, the benefit in terms of size of ice crystals has been evidenced. © 2018 International Institute of Refrigeration. All rights reserved.
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| 5. |
- Lindberg, Ulla, et al.
(författare)
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Certified energy consultant for increasednumber of retail grocery stores with low energy use, safe operation and low environmental impact
- 2018
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Ingår i: Refrigeration Science and Technology. - 9782362150241 ; , s. 376-384
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Konferensbidrag (refereegranskat)abstract
- This paper describes the framework for a proposed certification for energy consultants targeting the grocery sector, i.e. supermarkets. Thecertificationshould cover necessary knowledge and requirements, with the overall aim of increasing energy efficiency and reducing related costs for the store at the system level. Within the retail sector, supermarkets are the most energy-intensive buildings. Buildings intended for food sector applications need to be of a special design, with requirements that differ from other premises. Half of the electricity used is employed to keep food cold. However, energy efficiency can be improved through efficient equipment and increased knowledge, sometimes by 30-50% or more. This paper presents different skills and requirements needed by a certified energy consultant, CEC, working with energy efficiency in supermarket, from the retailer's perspective. Thus, the specifications can be used to further develop the certification area; energy consulting for supermarkets and good practice approaches targeting this area.
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| 6. |
- Lindberg, Ulla, et al.
(författare)
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Energy agreements regarding grocery stores for a sustainable society - Lessons learned
- 2018
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Ingår i: Refrigeration Science and Technology. - 9782362150241 ; , s. 152-159
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Konferensbidrag (refereegranskat)abstract
- In this study we aim to shed light on waste heat from commercial refrigeration, which is common but unnecessary. Excess heat is the heat which is not recovered, although it is possible to do so. We include heating for existing buildings: grocery stores as stand-alone, or within another building. VariousSwedish perspectives of the parties involved, tenant and landlord, are discussed. Theoretically and technically, it is not difficult to distributeexcess energy from a tenant to another receiver, which in turn uses the energy. However, to meet energy goals regarding energy consumption for heating buildings requires new and efficient approaches. The technique is already known and availableon the market. We suggest that availableenergy and heat recovery projects, contracts and agreements maysignificantly enhance the possibility of creating viable energy efficiency projects, and include excess heat. Results include lessons learned from the parties.
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| 7. |
- Makhnatch, Pavel, et al.
(författare)
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Characteristics of R454C and R455A as R404A alternatives in commercial refrigeration
- 2018
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Ingår i: Refrigeration Science and Technology. - : International Institute of Refrigeration. - 9782362150241 ; , s. 547-553
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Konferensbidrag (refereegranskat)abstract
- R404A will be soon restricted from usage in commercial refrigeration in the European Union (EU) due to the requirements of the EU Regulation on fluorinated gases. Therefore, new refrigerant HFO/HFC mixtures are being developed to replace it. This paper explores the R454C and R455A as R404A alternatives and compares the characteristics that can lead their imposition in the refrigeration market. The characteristics studied are components and composition, current penetration in the market, security issues, global warming potential, energetic performance, material and lubricant compatibility and, finally, most likely applications.
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| 8. |
- Makhnatch, Pavel, et al.
(författare)
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Field measurements of AR404A low-temperature supermarket refrigeration system retrofitted with R449A
- 2018
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Ingår i: Refrigeration Science and Technology. - : International Institute of Refrigeration. - 9782362150241 ; , s. 468-474
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Konferensbidrag (refereegranskat)abstract
- Current international regulations set incentives to replace refrigerants with high global warming potential (GWP) values using environmentally friendly alternatives. This study presents the field measurements of an indirect commercial refrigeration system retrofitted with R449A, an alternative to R404A with a GWP value of 1282 (67% lower than that of R404A). The system has been operated at low evaporation temperature conditions(secondary refrigerant temperatures from -34 to -25°C). The results indicate that the cooling capacity of the retrofitted system was 1.3% lower than that of the reference R404A system on average, while the COP values are higher when using R449A (8.1% increase on average). The compressor discharge temperature increase is approximately 18.5 K. As a conclusion, R449A can be used as a replacement to R404A in indirect low-temperature supermarket refrigeration systems given that implications of its higher compressor discharge temperature, lower mass flow and difference in transport properties are taken into consideration.
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| 9. |
- Xanthakis, Epameinondas, et al.
(författare)
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Evaluation of microwave assisted freezing (MAF) impact on meat and fish matrices
- 2018
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Ingår i: Refrigeration Science and Technology. - 9782362150241 ; , s. 176-181
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Konferensbidrag (refereegranskat)abstract
- Several preservation methods have been investigated, developed and exploited over the last years but freezing still remains one of the most popular among them which offers fresh-like characteristics on the food matrix after long period of storage. The freezing process of food matrices is affected by their dominant constituent which is water. The final quality of the frozen product depends on the phase transition or the crystallization process of changing water into ice. The size of the ice crystals is critical for the final quality of the frozen food. In the present study a novel more advanced experimental setup was designed and developed for the application of microwave radiation during freezing. The influence of microwave assisted freezing (MAF) on meat and fish matrices under different conditions was investigated and promising results regarding the microstructure of the frozen samples were acquired.
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