cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.18462/iir.gl.2018.1279
title: Advances in hybrid compression technology applied to ultra-low temperature and industrial refrigeration.

description: The Hybrid Compression (HC), introduced lately (Staicovici, 2015 a, b, c, 2016 a, b, 2017 a, b, c), is one of the most promising technology in ultra-low temperature refrigeration (ULTR) and ultra-high temperature heating (UHTH). This work continues research of ULTR and industrial refrigeration, presenting the HC-SECTOR cycle, a completion of HC technology. A simplified structure of this cycle, consisting of the coupling between an absorption technology section (ATS) and a mechanical vapor compression technology section (MVCTS), is given. Also, its 1st and 2nd principles effectiveness model is shortly presented by a lemma, proved here. Results are given for single-stage NH3-H2O ATS and NH3 MVCTS. As main input data, the evaporator and external sink source temperatures considered are: -75, -70, ..., -45°C, and +27°C, respectively. The main output data are the 1st and 2nd principles refrigeration effectiveness and HC refrigerant relative compressed volume. The results show HC-SECTOR cycle brings important improvements in refrigeration as compared to HC cycles elaborated so far and to MVC, increasing its feasibility, comparatively.
DOI: 10.18462/iir.gl.2018.1297
title: Evaluation and modelling of ice rink energy usage.

description: Ice rink operation requires significant amounts of energy and a typical single sheet ice rink uses about 1000 MWh per year, where 43% is used by the refrigeration system. To estimate the energy consumption of a refrigeration system, simulation tools have been developed such as Pack Calculation Pro, in parallel with empirical correlations that we have developed for the specific case of ice rinks. In the meantime, continuous energy monitoring and measurements are carried out in many ice rinks, providing the actual energy performance of the installation. Based on a few Swedish ice rinks, the aim of the study was to compare the results obtained with the numerical simulation software and our energy forecast to the actual performances of the refrigeration system. This analysis allowed us to adjust the different models. It led to satisfying results regarding the relative difference between the simulation and measurements for the energy consumption of the refrigeration system and its auxiliaries; less than 10% for a direct expansion CO2 system and less than 5% for an indirect CO2 system.
DOI: 10.18462/iir.gl.2018.1375
title: Selection of fluids for a polygeneration plant with LNG cold recovery.

description: Natural gas is forecasted to be one of the most important primary energy sources for the next decades. Particularly, Liquefied Natural Gas (LNG) demand is growing, mainly because of its flexibility in transport. Moreover, its cryogenic temperature makes LNG an important exergy source. However, the conventional LNG regasification process implies that LNG cold is not recovered, but it is wasted. In this sense, polygeneration is a promising way to exploit LNG exergy. The objective of this paper is the selection of the most suitable natural working fluids and heat transfer fluids for a polygeneration plant with cold recovery from LNG regasification. The polygeneration plants exploits the LNG cold for the simultaneous production of electrical power and cold at three temperature levels in a District Cooling network. The plant is not only analyzed from the thermodynamic point of view, but also its environmental impact is evaluated.
DOI: 10.17632/s5cy86h3sf.2
title: Large-scale borehole heat exchange temperature data in differing lithological units

description: Temperature data recorded at the interface of a u-tube and the grout of a borehole heat exchanger production well and water temperature as it entered and left the well field. The wells is a central well of a 144 well borehole heat exchanger. Temperature was recorded using a series of thermocouples attached to the u-tube at 50 foot intervals from 50 to 400 feet below ground surface. Temperatures were recorded every hour from 4/17/2017 through 6/23/2017. Temperature of the water entering and leaving the borehole heat exchanger was also recorded. Units are in degrees Celsius. Description of the column headers. Date_Time: Date and time of the temperature measurement. 50_degC: Temperature measurement at 50 feet below ground surface of the interface of the incoming water side of the u-tube and grout. 100_degC: Temperature measurement at 100 feet below ground surface of the interface of the incoming water side of the u-tube and grout. 150_degC: Temperature measurement at 150 feet below ground surface of the interface of the incoming water side of the u-tube and grout. 200_degC: Temperature measurement at 200 feet below ground surface of the interface of the incoming water side of the u-tube and grout. 250_degC: Temperature measurement at 250 feet below ground surface of the interface of the incoming water side of the u-tube and grout. 300_degC: Temperature measurement at 300 feet below ground surface of the interface of the incoming water side of the u-tube and grout. 350_degC: Temperature measurement at 350 feet below ground surface of the interface of the incoming water side of the u-tube and grout. 400_degC: Temperature measurement at 400 feet below ground surface of the interface of the incoming water side of the u-tube and grout. BHE_IN__degC: Temperature measurement of the water entering the borehole heat exchanger. BHE_OUT__degC: Temperature measurement of the water leaving the borehole heat exchanger.
DOI: 10.18462/iir.gl.2018.1119
title: CO2 vs. fluorinated refrigerants energy evaluation in a MT cabinet with DX-system.

description: Due to its low GWP100, CO2 is being implanted as a long-term solution in commercial refrigeration. However, the reduced direct effect of CO2 is contradicted by its high indirect effect - caused by the energy consumption of the refrigerating plants, especially in warm climates such as Spain -. The need for experimental data that compares the energy consumption of a DX-system using CO2 as a refrigerant with the current fluorinated refrigerants is the aim of this work, where two experimental facilities designed and
optimized for CO2 and R134a have been experimentally tested at three heat rejection temperatures using a cabinet for fresh product as cooling load. Results from experimental tests confirm that the performance of simplified CO2-systems is far away from HFC-systems and, therefore, it justifies the need to adopt new configurations to improve its energy consumption. In this sense, an alternative CO2 configuration based on double IHX has been presented and experimentally tested.
DOI: 10.18462/iir.gl.2018.1220
title: Analysis of a modified cycle design of a gas-fired absorption heat pump with a new flue gas heat exchanger.

description: Gas-fired ammonia/water absorption heat pumps (GAHP) can contribute substantially to the reduction of greenhouse gases in the context of heating. In recent years, only small increases of the efficiency could be achieved. For a significant increase a modification of the heat pump cycle is necessary. Common flue gas heat exchangers in GAHPs use the return flow of the heat distribution system to cool the flue gas below the dew point to condense water vapour. Especially in case of retrofit applications, the temperature in the heating system is too high to condense water vapour in the flue gas. Latent heat is thus dissipated into the environment. To use the latent heat under all operating conditions, a refrigerant cooled flue gas heat exchanger, which is installed between the evaporator and the absorber, is investigated within this work. A model based on mass, species, and energy balances was used to compare the common cycle design efficiency with the novel one. Measurements were conducted on an absorption heat pump with a heating capacity of 3 kW. Due to the new cycle design superheated ammonia vapour enters the absorber which leads to the necessity of investigations of potential impacts on the absorption behaviour.
DOI: 10.18462/iir.gl.2018.1232
title: About a more intuitive exergy efficiency calculus applied to heat pumping and working cycles and other basic aspects issued thereof.

description: Paper published in poster form during the conference. A more intuitive exergy efficiency calculus is proposed for absorption and mechanical vapor compression cooling, heating and working cycles. According to a lemma proved, the exergy efficiency of these cycles equals the relative to Carnot efficiency. Other simple thermodynamic processes obeying lemma are presented too. A basic theorem shows that 1st principle effectiveness COP has an exergy like behavior and it is linked together with entropy source in energy-processes and with natural force of non-equilibrium phenomenological thermodynamics in open steady-state physical and chemical processes. Two ammonia applications close paper.
DOI: 10.18462/iir.gl.2018.1283
title: Investigation of a hybrid compression absorption heat pump system for high temperatures.

description: This study introduces two simulation models for hybrid compression-absorption industrial heat pump cases: with two-stage piston compressor and a screw compressor. A heat source of 30℃ was utilized to achieve a heat sink outlet temperature of 115℃. The circulation ratio was varied to evaluate the effect on the COP and heating capacity. The system with a two-stage piston compressor with intercooling obtained a COP of 2.04 with the circulation ratio 0.72, which was 42% of the Lorenz COP. The intermediate pressure and compressor cooling were optimized. The system with a screw compressor had a lower performance.
DOI: 10.18462/iir.gl.2018.1350
title: Global market and policy trends for CO2 and ammonia in refrigeration.

description: The changing legislative landscape for fluorinated refrigerants is underpinning the market trends for natural refrigerants in various sectors globally. With an increasing uptake of HFC-free technologies there is a growing competition between different natural refrigerant-based systems. While ammonia has been widely used as the standard refrigerant in large industrial refrigeration for more than a century, new technologies using low-charge ammonia and CO2 challenge the status quo. With more than 12,000 CO2 transcritical stores in Europe and over 15,300 globally, CO2 transcritical technology is gradually gaining ground in different parts of the world. However, low-charge ammonia is being considered for application where it has traditionally not been used, such as HVAC and food retail. The paper evaluates the key market, technology and policy trends for CO2 and ammonia, presenting data on the number of installed applications and comparing the evolution in Europe, North America and Asia /Pacific.
DOI: 10.18462/iir.gl.2018.1383
title: Cold thermal energy storage integration in a large industrial refrigeration system.

description: Global warming is one of the greatest challenges our society faces today, and researchers strive to find solutions to reduce the emissions of greenhouse gases that accelerate the global warming effect. This paper describes a concept for a large cold thermal energy storage (CTES) system integrated in an industrial NH3/CO2 cascade refrigeration system for a poultry processing plant. The refrigeration system is fully centralized while oil-free CO2 is pumped to the freezing and cooling equipment. The CTES consists of closed tanks that contain stacks of heat exchanger plates with circulating CO2 on the inside and a phase change material (PCM) in the tank. During charging, the CO2 evaporates inside the plates while the PCM changes phase from liquid to solid. The purpose of CTES is to reduce daytime peaks in the energy use, e.g. charging the storage during night and weekends and discharging during times of peak refrigeration demand. The performance of the system is investigated through simulations with Modelica/Dymola.
DOI: 10.18462/iir.gl.2018.1394
title: Theoretical analysis for charge reduction in a 200 kW hydrocarbon high temperature heat pump.

description: Hydrocarbons with thermodynamic properties similar to synthetic fluids are alternative working fluid for high temperature heat pumps without the negative environmental impact of greenhouse gases. Though hydrocarbons have good performance as a working fluid for high temperature applications, they are constrained by high flammability. Hydrocarbons such as butane also have a high cost per kg. This study theoretically evaluates the opportunities to reduce the charge of a 200 kW hydrocarbon high temperature heat pump module that is designed for industrial applications. The theoretical analysis is based on an experimental test facility for component sizing references and design alteration possibilities. A charge reduction of 50 % was achieved from the analysis. By optimizing the design for charge reduction, an equivalent charge to the reference model has a 12.6 % increase in COP
DOI: 10.18462/iir.gl.2018.1403
title: Financial aspects of ejector solutions in supermarket and smaller industrial systems.

description: Financial analysis was performed to investigate the impact of add-on ejector solutions on a base CO2 system: booster or parallel compression. The ejector solutions were investigated are: gas ejectors and liquid ejectors for flooded evaporator configurations. The annual energy consumption of systems was simulated with Pack Calculation Pro for various locations around the globe. The energy saving is a crucial factor in the calculation of the total cost of a commercial or industrial installation. Another important financial parameter for the owner of the installation is the period required to recoup the funds expended in the investment.
The scope of the paper is not only to understand the level of energy saving on an annual basis for different CO2 type systems in various locations, but also to investigate financial aspects like payback times for ejector solutions in various systems and sizes and for different climates.
DOI: 10.18462/iir.gl.2018.1103
title: Assessment of factors affecting R290 concentrations arising from leaks in room air conditioners.

description: Currently R290 is used to a small extent in room air conditioners, such as split, portable and window types. Products are limited to relatively small cooling capacities due to refrigerant charge sizes being constrained to around 300 – 400 g, on account of maximum charge formulae within standards IEC 60335-2-40, ISO 5149-1 and EN 378-1. This is especially challenging in warm countries where the cooling load is greater and charge sizes need to be larger. Work is underway to improve maximum charge size determination methods for a given room size. As a contribution to this on going process, further research has been carried out to understand the factors that affect development of flammable concentrations within rooms in event of a leak. Parameters related
to the characteristics of room air conditioners and installations have been investigated experimentally by measuring R290 concentrations from releases and selected findings are described.
DOI: 10.18462/iir.gl.2018.1130
title: Ionic liquid : ammonia double-effect absorption refrigeration cycles for refrigeration in fishing vessels.

description: Ionic liquid (IL)-NH3 double-effect absorption systems are proposed to utilize the high-temperature exhausted gas (250-500°C) from engines with the purpose of delivering the required refrigeration of the fishing vessel. In this work, practical concerns on the stabilities, toxicities and viscosities of IL-based fluids have been discussed. Monte Carlo (MC) methods have been applied to extend the vapor-liquid equilibrium properties of selected IL-NH3 working pairs to high-temperature conditions. Additionally, a case study based on a specific fishing vessel has been carried out to investigate the economic feasibility of the proposed systems.
DOI: 10.18462/iir.gl.2018.1169
title: Experimental comparison of heat pump performance using CO2 or R134a as a refrigerant for electrical vehicles.

description: This paper experimentally evaluates the cooling and heating performance of CO2 and R134a heat pump systems applied in electrical vehicles. A mobile scroll type electrical compressor with 27 cc displacement was used for R134a system, and a commercial rotary type electrical compressor with 6 cc displacement was adopted for CO2 prototype system. Comparative experiments were carried out for these two systems in the calorimeter test facility. In addition, the effects of compressor speed, outdoor air temperature, outdoor air velocity and indoor air inlet temperature on system performance were also investigated. Experimental results concluded that CO2 system achieves comparable cooling capacity with R134a system, and performs a high heating COP and heating capacity in a cold climate. The advantage of CO2 heating performance will contribute to extending the driving range of electrical vehicles in a cold climate and making CO2 refrigerant more promising in the field of automobile air conditioner.
DOI: 10.18462/iir.gl.2018.1173
title: CFD simulations of a two-phase ejector for transcritical CO2 cycles applied to supermarket refrigeration systems.

description: The use of carbon dioxide (CO2), as a working fluid for large refrigeration systems, has grown tremendously in recent years. Factors such as its low cost, easy accessibility and environmentally friendly characteristics compared to HFCs and HCFCs, has made CO2 a viable alternative. To efficiently operate with CO2, the thermodynamic cycle needs high-pressure levels that can easily exceed the critical point due to the low critical temperature. By replacing conventional expansion valves with ejectors, the thermodynamic losses of the high-pressure throttling are mitigated, and the overall system performance is improved. To design and efficiently control the whole cycle, a thorough comprehension of the ejector fluid dynamics is mandatory. In this work, Computational Fluid Dynamics (CFD) is used to thoroughly investigate such a device. The employed CFD solver uses a modified form of the Homogenous Relaxation Model (HRM) to deal with twophase flows in a non-thermodynamic equilibrium state, per Colarossi et al. (2012). Preliminary numerical results for an ejector in supermarket refrigeration system operating conditions are presented and discussed.
DOI: 10.18462/iir.gl.2018.1176
title: Caloric properties of R600a solutions in compressor oil containing fullerenes C60

description: New experimental data on the saturated liquid heat capacity for the R600a/mineral oil solutions (ROS) is reported in the paper. Data on the two-phase isochoric heat capacity was obtained for different oil fractions of the refrigerant in the temperature range from 260 to 330 K. The obtained information was used to calculate the caloric properties of the ROS. Moreover, an influence of fullerenes C60 on the caloric properties of mineral oil was examined. The measurements of the heat capacity for the ROS, compressor oil and compressor oil containing fullerenes C60 were performed using an experimental setup, which implements a direct heating method in adiabatic calorimeter. In addition, the heat capacity of oil and oil containing fullerenes C60 was measured using differential scanning calorimetry. The effect of increasing the heat capacity of the compressor oil with the additives of 0.0020 kg·kg-1 of fullerenes C60 was observed.
DOI: 10.18462/iir.gl.2018.1229
title: Saturated vapor condensation of hydrocarbons inside a 4mm ID horizontal smooth tube.

description: This paper presents the comparative analysis of three hydrocarbon refrigerants: R600a (isobutane), R290 (propane) and R1270 (propylene) in saturated vapor condensation inside a 4 mm ID horizontal smooth tube. New experimental tests were carried out with R600a at 40 °C of saturation temperature, with refrigerant mass flux in the range 75–300 kg m−2 s−1, whereas the same authors (Longo et al. 2017) previously presented measurements for propane and propylene, at the same operating conditions. The experimental heat transfer coefficients and frictional pressure drop in the forced convection condensation regime were then compared against some correlations available in literature.
DOI: 10.18462/iir.gl.2018.1325
title: Reactivation of ice rink sorption dehumidifiers with recovered heat.

description: The dehumidification function in ice rink is energy intensive with an annual energy usage in the range of 50 to 150 MWh for a typical single sheet ice rink. The sorption process is the most common dehumidification solution in ice rinks since it offers good performance at low process air temperatures. Typically, the sorption process is reactivated using heat generated by electricity or natural gas which both may provide high and convenient reactivation air temperatures. More recent dehumidifier designs allow lower reactivation air temperatures which enables the use of recovered heat from a refrigeration system. The carbon dioxide refrigeration process, which is becoming increasingly popular in ice rinks, is particularly suitable in this context. Carbon dioxide refrigeration systems provide more heat at a higher temperature level than other refrigerants which is a perfect match to the dehumidification heat demand. Two different heat recovery supported dehumidification concepts are presented and referred to as generation 1 and 2. The first is a “hybrid” using recovered heat as well as electricity whereas the second uses solely recovered heat for the reactivation. Field measurements show that the first concept can save about 37% of the annual electrical demand, related to dehumidification, which in the specific ice rink corresponds to 24 MWh. Using the second concept increased the actual saving with as much as 86% which in that ice rink corresponded to 63 MWh. The total energy for dehumidification is very different in ice rinks which depends on the humidity load situation but also on the control strategy. If the second concept would be applied in the ice rink with the highest total energy usage the absolute saving potential would be as high as 134 MWh per season. The latter requires, however, that the heat recovery system can supply enough heat and on the required temperature level. In practice the second concept requires a CO2 refrigeration system or heat pumps coupled to the heat recovery system.
DOI: 10.18462/iir.gl.2018.1339
title: Experimental comparison between different heat pump designs working with propane to control subcooling for sanitary hot water production.

description: Subcooling significantly influences the heat pump performance. An optimal value based on external conditions exists. In this frame, three different propane heat pump prototypes for sanitary hot water production, where high temperature lifts at the secondary fluid take place (so the benefit from high degrees of subcooling is maximized), have been tested. This work experimentally compares the two most interesting prototypes. The most important differences between both are the subcooling control (by a throttling valve in one case (10K2V) and by the expansion valve in the other (0K1V)) and the superheat control (by the expansion valve in 10K2V and zero in 0K1V). Results show the capability of both prototypes to operate with similar COPs than other leading systems based on transcritical cycles. COP differences up to 5.5% between both and the extra valve required in 10K2V demonstrate the importance of the configuration to develop the most thermo-economic heat pump solution.