cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.18462/iir.nh3-co2.2017.0013
title: PVT-measurements for high-temp ammonia heat pump lubricants.

description: Ammonia (R717) is a commonly used refrigerant, often used in food, beverage and chemical industry for example. Recently, R717 is also used in high-temperature heat pumps. Typically, hydrocarbon oils like mineral oil (MO), polyalphaolefine (PAO) and alkyl benzene (AB) are applied for lubricating R717 compressors. In our previous experiments as well as the latest literature it was found that at high temperatures ammonia dissolves in these oils and thus affects the viscosity stronger than expected. The solubility of R717 increases from around 1 % at room temperature to more than 10 % at temperatures above 100 °C. For this reason, it is necessary to think about generating corresponding PVT diagrams (also known as Daniel Plots) for such systems. The paper deals with measurements of solubility, vapor pressure, density and viscosity of four different oils mixed with ammonia up to 50 bar and 140 °C. The density was determined based on the bending vibration principle; the pressure of three to five refrigerant-oil-mixtures (90 – 99 wt.% oil) per oil was determined with a static measurement method. With the results from the pressure measurement, the miscibility gap was calculated. To prevent segregation during the viscosity experiment a complex measurement setup was developed. After measuring the viscosity of the pure oils and the mixtures, the viscosity reduction was calculated and Daniel Plots were created. For the first time, high temperature behavior of several types and viscosity grades of hydrocarbon oils with ammonia can be compared by Daniel Plots to choose the best oil for high-temperature ammonia heat pump applications.
DOI: 10.18462/iir.nh3-co2.2017.0028
title: The role of the lubricant chemistry in a R-744 refrigeration plant oil - return and lubricity. comparison between two chemistries using data from a real plant.

description: The lubricant plays an important role in the operation of a refrigeration plant, and understanding the effect of the lubricant is paramount. Since the lubricant is exposed directly to R-744, the solubility has to be balanced between enhancing lubricant flow when in the system so that oil return is sufficient for reliable operation, versus reduction in viscosity in the compressor due to R-744’s properties as an effective solvent. In addition to the lubricating properties, lubricants must also exhibit excellent chemical and thermal stability. 
There are two main barriers for the expansion Southward in Europe of R-744 refrigeration systems: the higher operating pressures (related to design robustness), and the maximum discharge temperature allowable by the lubricant to avoid its thermal breakdown. Two chemistries are available to the contractors for R-744 refrigeration plants design and operation: POE (Polyol-Ester) and PAG (Poly-Alkylene-Glycol). In this study, benefits and drawbacks of each chemistry will be explained, as well as practical points identified to help the technicians to select and work with the best operating conditions, including the maximum allowable discharge temperature. 
Using commercial grades properties and technical data for both ISO VG68 PAG and ISO VG85 POE, key properties (viscosity and percentage of R-744 dissolved in the oil) have been determined in each of the system components (gas cooler, evaporator, liquid reservoir, crankcase). This will enable the technicians to understand and take better decisions with the knowledge of what will happen once in operation.
DOI: 10.18462/iir.nh3-co2.2017.0029
title: CO2 refrigeration system for ice production in snow making generators at ambient temperatures above 0°C.

description: In many destinations in Europe and Northern countries, the snow is not available when the skiing arrangement is going to take place. There is an increasing interest to install ice machines to supplement the stored snow from the previous year, giving possibility to start the skiing season as early as possible. The capacity of such machines is 50 to 100 tonnes of ice per day. Flake ice system with a production capacity of 50 tons day-1 was modelled in EES, to investigate the thermodynamic performance at different ambient temperatures. The flake ice model shows that single stage systems consume less energy than two stage systems. The U-value and ice growth rate for the flake ice drum are highly dependent on the ice thickness, and the ice thickness influence the heat transfer from water to CO2. COMSOL calculations reveal that increasing the number of refrigerant pipes in the flake ice drum above 200, do not affect the temperature distribution on the freezing surface too much. The thickness can be optimized regarding the structural strength, rather than the heat transfer.
DOI: 10.18462/iir.nh3-co2.2017.0040
title: Off-design of high temperature compression-absorption heat pump.

description: Most heat pumps are designed for optimal performance at one specific operation point. In real industrial applications though, the operating load and conditions change, thus, the heat pump should not only be considered at its optimum, but also, how and to which extend the off-design conditions affect its overall performance. A holistic approach for the most suitable choice of heat pump thus should include calculations and/or simulations of the heat pump at varying load and conditions. In this work, a compression-absorption high temperature heat pump using water and ammonia was studied. The load was varied from 17% to 159% of the design point based on a measured demand in the industry, yielding average COPs of 2.02-2.08 for the different cases considered, with minimum and maximum values of 1.72 and 2.26. The absorption and desorption temperatures were also changed, showing strong impact on performance. The COP then varied between 1.67 and 2.35 Compressor efficiency was not kept constant, to fully exploit the effects. Several suggestions for improvement were identified.
DOI: 10.14455/trf.res.2006.3
title: ประวัติศาสตร์พระพุทธศาสนาเมืองแจ๋มหนึ่งร้อยปี /
DOI: 10.14455/trf.res.2006.5
title: ประวัติศาสตร์ขุนหลวงวิลังคะ กับการเสริมสร้างความเข้มแข็งของชุมชนเมืองก๊ะ ตำบลสะลวง อำเภอแม่ริม จังหวัดเชียงใหม่ /
DOI: 10.14457/kku.the.2006.415
title: ความต้องการของเกษตรกรผู้ปลูกมันฝรั่งในจังหวัดสกลนคร /
DOI: 10.14457/tu.the.2006.269
title: ความต้องการข้อมูลและความพึงพอใจของผู้โดยสาร ต่อเครื่องมือสื่อสารการตลาด ของสายการบินไทยแอร์เอเชีย /
DOI: 10.14457/tu.the.2006.270
title: ประมวลศัพท์เฉพาะเกี่ยวกับสัญญาเช่าที่พัก /
DOI: 10.17632/vc2nbwzddd.1
title: Data for: Morphometrics, Craniofacial Disease Genes, and the Quest for the Genetic Basis of Facial Morphology

description: Includes raw and processed morphometric data, genotypes, and questionnaire data for 91 participants. Each .zip in the case of the portrait and profile data or excel spreadsheet in the processed data .zip file includes either a ReadMe.txt file or a separate Guide sheet with information pertaining to the data within. For questions or clarifications, please contact the author at baileythegreen@gmail.com.
DOI: 10.18462/iir.nh3-co2.2017.0001
title: Mega-trends in industrial refrigeration.

description: This paper looks at several external factors that are likely to influence the decisions taken by designers of industrial refrigeration systems over the next twenty five years. Four factors are considered and in each case they are examined in the light of the three common contexts of increased urbanisation, growing environmental awareness and ever-present pressure on cost. The factors are carbon reduction, automation, globalisation and universality (meaning the rapid transfer and sharing of information and knowledge).
DOI: 10.18462/iir.nh3-co2.2017.0009
title: Modelling of split condenser heat pump: optimization and exergy analysis.

description: This paper presents a numerical study of a split condenser heat pump (SCHP). The SCHP setup differs from a traditional heat pump (THP) setup in the way that two separate water streams on the secondary side of the condenser are heated in parallel to different temperature levels, whereas only one stream is heated in a THP. The comparison between the SCHP and a THP was made for equal heat load and equal total pressure drop on the secondary side. It was found that the SCHP setup offered solutions that resulted in smaller/more compact plate heat exchangers for reaching the same COP as a traditional unit. For a water temperature of 40°C/85°C and an evaporating temperature of 5°C, the total area of the two plate heat exchangers was reduced by 3%. When using the SCHP setup the exergy destruction was slightly smaller compared to the THP.
DOI: 10.18462/iir.nh3-co2.2017.0021
title: Integrated CO2 refrigeration and AC unit for hot climates.

description: An integrated refrigeration and AC system with CO2 as the only working fluid for use in very hot climates (+45 °C) has been designed, modelled and simulated in Dymola. Based on the simulation results, its feasibility is proven. The system can achieve 3 kW of cooling capacity at the low evaporation temperature level of -28.6 °C, 10 kW at the medium temperature level (-3.2 °C) and 20 kW for AC at an evaporation temperature of +12.6 °C. The use of ejectors is essential for the system performance at these extreme ambient temperatures, and enables an, until now, impossible application for the natural, environmentally friendly refrigerant CO2. The CO2 system achieves a similar performance compared to existing solutions applying synthetic refrigerants with high GWP and ODP, which are typically applied nowadays in high ambient temperature regions.
DOI: 10.18462/iir.nh3-co2.2017.0022
title: A new approach for cold thermal energy storages in supermarket refrigeration systems.

description: Supermarket refrigeration systems have a significant energy demand to preserve the quality of valuable food products. Thus, several approaches to reduce the energy demand, and to solve other challenges a supermarket refrigeration system faces have been considered in the past years. Some of the main challenges that have been addressed are the temperature instability of the food products in the display cabinets/freezers during defrost period. Other issues that have been considered are the high electricity network costs due to the grid dependency and peak power demand. One of the solutions proposed is the implementation of cold thermal storages (CTES) in combination with the widely applied CO2 refrigeration system of supermarkets. This paper proposes a new approach by implementing the cold storage on top of the display cabinet, and apply the thermosiphon principle for the heat exchange between the evaporator and the cold storage, when the cabinet is disconnected from the central CO2 refrigeration system. One of the advantages for this concept is the utilisation of currently unapplied space. Locating the CTES on top, it will not limit the size of the display cabinet, since normally, the space on top is not used for any other purposes and space in supermarkets is limited. Simulations at different boundary conditions will be conducted in order to assess the performance of this new concept.
DOI: 10.18462/iir.nh3-co2.2017.0030
title: Performance test methodology for the LCCP determination of supermarket and other integrated systems.

description: A new flexible supermarket R-744 refrigeration unit has been implemented in the laboratories at NTNU/SINTEF. The unit is fully equipped with real display cabinets for both medium and low temperature, as well as seven large volume counter flow glycol heat exchangers to simulate the entire load of a supermarket. The entire range of alternative system architectures can be experimentally investigated, from a simple booster system, parallel compression towards ejector supported parallel compression. Various air conditioning (AC) loads can also be handled, to demonstrate the performance and potential of integrated R-744 systems. 
Life Cycle Climate Performance (LCCP) tools are commonly applied to compare different system architectures. These tools are very detailed, accounting for most of the Greenhouse Gas (GHG) releases from CO2 emissions due to energy usage (indirect) and CO2 equivalent emissions from other operations (direct CO2equ) from “cradle” (refrigerant and product manufacturing), through use, to “grave” (recycling and disposal) for a product. The results of LCCP investigations are mainly dependent on the energy usage, i.e. the energy demand for different load conditions at various ambient conditions, often expressed as the Seasonal Energy Efficiency Rating (SEER) of the refrigeration unit. Several options are proposed in the literature for the determination of the LCCP in systems such as mobile air conditioning (MAC), heat pumps or refrigeration systems, but there is no approach for integrated units, i.e. equipment that meet simultaneously more than one load. This paper addresses this issue and suggests a possible way to deal with these cases.
DOI: 10.15468/y6rwap
title: New records of poecilostomatoid copepods (Crustacea) from a coastal system in the Colombian Caribbean with notes on morphology

description: This dataset contains the digitized treatments in Plazi based on the original journal article Juan M. Fuentes-Reinés, Eduardo Suárez-Morales (2017): New records of poecilostomatoid copepods (Crustacea) from a coastal system in the Colombian Caribbean with notes on morphology. Check List 13 (5): 513-523, DOI: 10.15560/13.5.513
DOI: 10.17632/4n8p7wmc4x.1
title: Data for: The Pyk2/MCU Pathway in the Rat Middle Cerebral Artery Occlusion Model of Ischemic Stroke
DOI: 10.17632/v8n2gz6szz.1
title: Data for: Development of a SNaPshot® Multiplex system for the typing of SNPs involved in the adaptive response to high altitude hypoxia

description: Suplementary info
DOI: 10.18462/iir.nh3-co2.2017.0002
title: Efficient very low charged ammonia systems.

description: This paper discusses the options for expanding use of ammonia as refrigerant in densely populated areas by utilizing ultra-low-charged air or water cooled chillers for air conditioning, refrigeration or high side of the cascade system. The paper presents a proposal for defining terminology in low charged systems (Ultra Low, Very Low and Low charge) and also the importance of definition of the allowable charge that would expand the use of ammonia chillers treating them equally as when using A2L refrigerants. The paper also shows development in large low charged units for industrial refrigeration as well as some new ultra-low charged ammonia chillers.
DOI: 10.18462/iir.nh3-co2.2017.0019
title: Reduction of energy consumption by applying a new generation of CO2 compressors.

description: The development of transcritical CO2 systems in commercial refrigeration can be considered to be in a transition phase from cutting edge to state-of-the-art technology. However, the stress field of new developments is strong and characterized by challenging demands from the market: Further improvement of the annual energy efficiency, reduced system complexity and a decreased cost of ownership. One key to success in commercial refrigeration is the application of a new generation of energy efficient CO2 compressors in a so-called baseline system. The features of this highly efficient compressor range, which is called ECOLINE+, is explained in this paper. The European standard EN13215 is considered as the standard method for the evaluation of the annual energy efficiencies. A more complex and time consuming method to calculate the annual energy efficiency is to consider the prevailing climate, more specific load profiles, the system configuration, operating times and resulting operating conditions of the compressors applied. This work provides an analytical study of different methods to calculate the annual energy efficiency for the new compressor generation compared to the standard compressor range and discusses the results of the comparison.
DOI: 10.18462/iir.nh3-co2.2017.0025
title: The performance evaluation of CO2 transcritical booster and R290/R744 cascade refrigeration systems for different cities in Turkey.

description: CO2 as a natural and fully environmentally friendly refrigerant has become more preferable in refrigeration systems in recent years. Since its critical temperature is much lower than that of other refrigerants. It is mostly used in cascade refrigerant systems as a low temperature cycle fluid. On the other hand, CO2 may be used in single-stage transcritical refrigeration systems. In this study, performance of two natural refrigerant solutions, trans-critical booster CO2 refrigeration system with ejector and a R290/CO2 cascade refrigeration system are examined theoretically by using EES software. Operating conditions are determined to represent different climatic regions in Turkey using summer dry bulb temperatures of various cities. The trans-critical and the cascade system are assumed to operate at two different evaporation temperatures of -10°C and -25°C,respectively. The overall EER values for each system with respect to the same ambient and evaporation conditions are compared and evaluated. Finally, performance of both systems has been compared and the appropriate solution for each city has been suggested.
DOI: 10.18462/iir.nh3-co2.2017.0003
title: Low charge packaged ammonia refrigeration systems.

description: Ammonia has been used as a refrigerant for over 100 years. Traditionally this has been in industrial applications where the system is built on site with distributed pipework and a large refrigerant charge. The phase down of global warming HFC refrigerants under the EU F-Gas regulation will require the development and application of new refrigerants and systems. This provides an opportunity for the wider use of ammonia, particularly in smaller scale applications. Concerns with toxicity and flammability need to be addressed, along with increased capital cost. This paper looks at the definition of ‘low charge’ and recent developments in system design and technology aimed at reducing charge. A number of different system types are discussed along with component design and selection. These include both site built and factory packaged system.
DOI: 10.18462/iir.nh3-co2.2017.0024
title: Integrated R744 ejector supported parallel compression racks for supermarkets. Operation conditions.

description: The share of the energy consumption of supermarkets in the total national consumption cannot be neglected, since it reaches up to 5%. In addition, the electricity used for the refrigeration, and heating, ventilation and air conditioning (HVAC) systems is the highest share of the total energy demand of the supermarket. Therefore, any enhancement of the performance of these systems will have an environmental and cost impact both on the supermarket sector and on the country itself. 
R744 appears as the preferred solution for centralized commercial refrigeration systems, however, it is crucial to improve their efficiency to eliminate previous geographical limits of applying these refrigerant and to make these units competitive in warmer climates. Therefore, it would wise to implement components such as ejectors and a parallel compression suction group in the R744 refrigeration units, and to meet and integrate all the different demands of a supermarket; refrigeration, HVAC and domestic hot water (DHW), with a single unit. 
This new concept of integrated R744 ejector supported parallel compression racks needs to be further studied, since it involves many control and optimisation issues never approached before, such as the floating pressure of the receiver, the air conditioning (AC) ejectors with pressure lift control, the use of compressors with pivoting suction group connections, etc. This study is part of the SuperSmart-Rack project, funded by the Norwegian Research Council and industrial partners. In this paper the optimization of operation conditions is approached with steady state simulations using a numerical model based on boundary conditions of the experimental facility available in the laboratory of NTNU/SINTEF in Trondheim.
DOI: 10.18462/iir.nh3-co2.2017.0026
title: Multi-physics simulation of a CO2 gas cooler.

description: A CFD model to simulate CO2 gas coolers is presented: the adoption of an equivalent approach allows to reproduce the effects of an extended finned surface while drastically reducing the computational effort. The model is validated with experimental results available in the open literature. The contemporary solution of both convection and conduction allows highlighting the impact of conduction along the tubes and the supporting end plates and provides satisfactory matching with experimental results: total heating power is forecast within 2.5%, while the maximum temperature deviation between the simulated and experimental heat exchanger curves temperature is 3.8, when the CO2 temperature is as high as 108 °C. This thermal CFD model allows to evaluate the 3D effects of the air maldistribution in terms of temperature, heat transfer coefficients, and cooling power, thus opening the way to the simulation and optimisation of complete finned coil and fan gas cooling systems.
DOI: 10.18462/iir.nh3-co2.2017.0031
title: Carbon dioxide as a possible low temperature refrigerant.

description: In this paper considerations will be given regarding the use of the carbon dioxide phase change from solid to gaseous state for low temperature cooling. Up to now, for the temperature range between -50 °C and -90 °C mainly refrigerants containing trifluoromethane (R-23) or hydrocarbons (e.g. propane or ethane) are used. So far, the triple point of carbon dioxide is limiting the application of the evaporation process used in conventional compression refrigeration. Below -56.6 °C carbon dioxide is only present either as a solid or as a gas without the liquid state. The most significant disadvantage of fluorinated low temperature refrigerants is their very high global warming potential. On the other hand, hydrocarbons - having very low global warming potentials - are flammable and thus have limited applications. A method will be described for the use of carbon dioxide in the form of dry ice for low temperature cooling as a climate-friendly alternative to HFC and flammable refrigerants. A TEWI analysis will show the energy advantage of the use of sublimation cooling in comparison to a cascade cooling system with the refrigerants R-404A and R-23.
Experimental results will be presented that demonstrate a solution of a sublimator with a solvent as heat exchanger fluid. This approach results in an improved cooling efficiency due to the higher heat transfer rate of sublimated dry ice in a liquid. Non-flammable per-fluorinated ketones and hydro-fluorinated ethers with low global warming potentials are shown to be suitable fluid classes for this task. Experimental results obtained with two different fluids will be given.
DOI: 10.18462/iir.nh3-co2.2017.0034
title: Global market and policy trends for CO2 and ammonia as natural refrigerants.

description: The paper will review the main market trends for the development of natural refrigerant solutions, analyse the key factors underpinning these trends, and review the main barriers that continue to prevent wider uptake in several sectors globally. It will present figures on the number of CO2 installations in Europe, with a special focus on the evolution in southern Europe, where high ambient temperature conditions present a particular challenge. The paper will subsequently compare the evolution in Europe to that in other markets in Asia/Pacific and North America. The paper analyses key policy drivers and trends impacting the market, such as
the development of low-charge ammonia systems, increasing competition between natural refrigerants in several applications and the state of the training offer in Europe and North America. It will conclude by pointing to the challenges ahead for both CO2 and ammonia-based applications.