L' avenir des Arénas Québécois

«Des expertises sont présentement menées et nous voulons attendre de savoir quel est le problème exactement avant de tirer des conclusions quant à l'avenir de l'aréna», explique Claude Raymond, chargé de communication à l'arrondissement Villeray–St-Michel–Parc-Extension.

Les utilisateurs de l'infrastructure devront patienter jusqu'au mois de décembre avant de connaître le sort qu'on leur réserve.

«La Ville m'a parlé de trois scénarios possibles», relate Stéphane Robert, président de l'Association de hockey mineur de Villeray (AHMV), principale victime de la fermeture. «En premier lieu, les pièces défectueuses pourraient être réparées. Sinon, il pourrait y avoir un changement complet du système de réfrigération. Ou encore, l'aréna pourrait subir un changement de vocation.»

Une chose est sûre, AHMW a dû changer d'adresse et s'installer à l'aréna Howie-Morenz pour la saison à venir, ce qui entraîne de nombreuses complications (voir autre texte).

600 000$ plus tard, patinoire inutilisable

En 2003, 500 000$ avaient été investis à Jean-Rougeau pour de nombreuses rénovations au niveau du plafond, des douches, des toilettes, du recouvrement du plancher et pour changer la peinture qui s'écaillait sur les murs.

Et le système de réfrigération? Il a absorbé une portion de l'investissement de près de 100 000$ fait en 2004, alors que l'arrondissement avait changé le déshumidificateur, réparé partiellement le collecteur de saumures et remplacé les moteurs des quatre compresseurs du système de réfrigération.

Pour sa part, le maire de la Municipalité de Saint-Ambroise, monsieur Marcel Claveau, se réjouit des effets positifs de ces travaux qui favoriseront un meilleur rendement des installations, en plus de renforcer le pouvoir d'attraction de sa municipalité et de contribuer au développement économique et touristique de la région.

Une aide financière de 470 millions de dollars, provenant du FIMR et assumée à parts égales par le gouvernement du Québec et le gouvernement du Canada, est offerte aux municipalités et aux organismes non gouvernementaux du Québec. Avec la participation financière de ces municipalités et organismes, ce sont quelque 700 millions de dollars de travaux qui pourront ainsi être réalisés. Le FIMR poursuit plusieurs objectifs : améliorer les infrastructures collectives, la qualité de l'environnement ainsi que la qualité de vie des citoyens et soutenir la croissance économique à long terme.

Ce programme, qui sera en vigueur jusqu'au 31 mars 2010, est géré par le

ministère des Affaires municipales, des Régions et de l'Occupation du territoire du Québec. La responsabilité du gouvernement du Canada relative au programme a été confiée à Développement économique Canada. La population est d'ailleurs invitée à visiter, le dimanche 4 octobre 2009, de 13 h à 16 h, les nouvelles installations de l'aréna.

Vapour Compression Cycle

The Minimum Amount of Work to Drive a Heat Pump is defined in terms of the Absolute Temperature Scale

Here we show again the diagram that was used to help explain the Reversible Carnot Cycle. It shows a reversible engine E driving a reversible heat pump P. The relationship between Q1, Q2 and W depends only on the temperatures of the hot and cold reservoirs, just as Carnot predicted. But temperature must be defined in a more fundamental way. The degrees on the thermometer are only an arbitrary scale. Kelvin took the bold step in 1851 of defining an absolute temperature scale in terms of the efficiency of reversible engines:

The ideal "never attainable" efficiency is the ratio of work output to heat input (W/Q1) of the reversible engine E and it equals: Temperature Difference (T1 - T0) divided by the Hot Reservoir Temperature (T1). It is known as the Carnot efficiency, taking its name from Sadi Carnot.

The device P can be any refrigeration device we care to invent, and the work of Kelvin tells us that the Minimum Work, W necessary to lift a quantity of heat Q2 from temperature T0 to temperature T1 is:

Q2 multiplied by the ratio Temperature Difference (T1 - T0)/Cold Reservoir Temperature (T0). The temperatures must be measured on an Absolute scale.

Choose a fluid, or refrigerant, which vaporizes at a lower temperature than the space to be cooled. Heat then flows from the cool space (downhill) and vaporizes the refrigerant. This is represented by the section 1 - 2 of the orange line. Then, instead of just letting it boil away and disappear as vapour, it is captured, and pressurized (2 - 3). At the high pressure its boiling point, or evaporating temperature is much higher. So it can condense at this higher temperature, giving up its latent heat which flows (downhill again) to the warm air outside (3 - 4). When it has become a liquid, the pressure is reduced (4 - 1) and the process can start again.

This is the most widely used process for providing cooling. It is called the Vapour Compression Cycle, and it finds application on equipment ranging from domestic refrigerators and freezers to large cold stores and building air conditioning systems.

Pressure - Enthalpy

In order to study this process more closely, refrigeration engineers use this pressure - enthalpy diagram. "P" is the symbol for Pressure, and "h" is the symbol for Enthalpy. This diagram is a way of describing the liquid and gas phase of a substance. On the vertical axis is pressure, and on the horizontal, enthalpy. Enthalpy can be thought of as the quantity of heat in a given quantity, or mass of substance. The curved line is called the saturation curve and it defines the boundary of pure liquid and pure gas, or vapour. In the region marked vapour, its pure vapour. In the region marked liquid, its pure liquid. If the pressure rises so that we are considering a region above the top of the curve, there is no distinction between liquid and vapour. Above this pressure the gas cannot be liquified. This is called the Critical Pressure. In the region underneath the curve, there is a mixture of liquid and vapour.

Varieties of Natural Refrigerants

Ammonia is a very good refrigerant and is used to a significant extent in large warehouses. Ammonia is toxic and, under certain limited conditions, flammable and even explosive. However, with its intense, pungent odor, it is a self-alarming refrigerant. Ammonia has emerged as a refrigerant for water chillers in Europe. These units are entirely self-contained, including a gastight cabinet that houses the entire unit and a water tank to dissolve any ammonia in case of a leak. These measures, to be sure, increase costs considerably.

Hydrocarbons are excellent refrigerants, but they are also flammable and explosive. In North America, any flammability risk is unacceptable, but some countries in Europe and elsewhere have less-stringent liability laws. Since the mid-1990s, virtually all refrigerator production in Germany has used hydrocarbons as the working fluid. Some heat pump manufacturers whose systems are installed entirely outdoors have followed suit, and some commercial installations have recently become publicly known. Nevertheless, the danger of fire remains an overriding concern. To address this challenge with safety features, the cost of a system would have to be increased by about one-third.

Carbon dioxide is a refrigerant that operates at very high pressures in a transcritical cycle for most operating conditions. Thus the refrigerant condenser of a conventional refrigeration system serves now as a cooler for supercritical fluid. Only after the expansion process is liquid carbon dioxide available to provide cooling capacity through evaporation. Because of the nature of the transcritical cycle, the efficiency of carbon dioxide is quite poor. However, this is its only disadvantage. All the other characteristics of carbon dioxide are very favorable. It is environmentally safe, has very low toxicity, and allows for extremely compact systems. The vapor pressure of CO2 is approximately seven times higher than that of R-22. Moreover, the supercritical CO2 has a higher density than subcritical fluids, so there is potential to reduce the size of hardware. There are indications that with modern materials and technologies, the weight of CO2 heat exchangers can be reduced considerably, especially for tap water heating, with essentially the same performance.

Natural Refrigerants & Carbon Dioxide

Substances such as air, water, ammonia, hydrocarbons, and carbon dioxide may provide solutions to the problem of finding environmentally acceptable refrigerants.

By Yunho Hwang, Michael Ohadi, and Reinhard Radermacher
Refrigeration and air conditioning play important roles in modern life. They not only provide comfortable and healthy living environments, but have also come to be regarded as necessities for surviving severe weather and preserving food. Unfortunately, accelerated technical development and economic growth in much of the world during the last century have produced severe environmental problems, forcing us to acknowledge that though these technological advances may contribute to human comfort, they also can threaten the environment through ozone depletion and global warming. Aside from cost reduction, these concerns are the biggest driving forces for technical innovation in the field of refrigeration and air conditioning.

Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs)—used as working refrigerants in refrigerators and air conditioners as well as blowing agents in foams—are now being regulated because of their contribution to ozone depletion. Hydrofluorocarbons (HFCs) could be useful as short- and midterm replacements, but may ultimately not be suitable, owing to their high global-warming potential (GWP). Accordingly, a long-term solution will require the use of natural refrigerants. The refrigerator and automotive air-conditioning industries have already begun to address the challenges of replacing HCFCs, including R-22, and, eventually, HFCs on a global level.

The second, more important reason, dealt with thermodynamics. Gerrard says that to reach the operating temperature that they require (–18 DegF) using a CO2 system would have meant using two compressors in order to reach the same energy efficiency as the hydrocarbons.

When choosing propane, they were initially concerned about safety issues. “The first question we had was the flammability of the refrigerant,” he says. “But, we knew that isobutane and propane have approximately the same flammability rating and that in the year 2000, there were about 120 million domestic refrigerators and freezers using isobutane and we weren’t aware of any accidents.”

Unilever undertook a number of risk assessments before the introduction of the hydrocarbon cabinets. The company also did leak testing and found that the leak rates for hydrocarbons in operation were “very, very low,” he says, in line with HFC refrigerated cabinets.. Leak rates are in the range of grams per year, he says, and at this rate it was highly unlikely that flammable mixtures could be formed.

In the US new rules come into effect on Jan. 1, 2010, restricting the use of hydrochlorofluorocarbons in refrigerants for air-conditioning systems, geothermal heat pumps and the chillers used to cool large residential and office buildings.





ARENA, ICE RINK, COMPRESSEUR QUEBEC REFRIGERATION, WWW.SDREFRIGERATION.CA

Le réfrigérateur domestique

Le réfrigérateur a été inventé en 1876 par Carl on Linde. Mais d'autres inventeurs s'attribuent cette paternité, parce que cette technologie a mis du temps à se développer. Une des premières utilisations de la réfrigération domestique a eu lieu au domaine de Biltmore à Asheville, en Caroline du Nord, États-Unis, autour de 1895.

Le réfrigérateur à absorption de gaz, qui se refroidit par l'utilisation d'une source de chaleur, a été inventé en Suède par Baltzar von Platen en 1922. Plus tard il a été fabriqué par Electrolux et Servel. Aujourd'hui il est utilisé dans les maisons qui ne sont pas reliées au réseau électrique et dans des camping-cars.

Développement moderne des réfrigérateurs

Réfrigérateurs domestiques

Ceux-ci se composent généralement de compartiments de refroidissement et de congélation et peuvent avoir quatre zones de température : -18°C ou 0°F (congélateur), 0°C ou 32°F (viandes), 4°C ou40°F (réfrigérateur) et 10°C ou 50°F (légumes), pour le stockage des différents types de nourriture. Le volume d'un réfrigérateur se mesure en litres.

Dans les modèles récents, un affichage à cristaux liquides suggère la température à utiliser pour les divers types de nourriture à conserver et montre la date limite de consommation des produits.

Quelques modèles incluent un système pour avertir d'une panne de courant, avec une fonction de mémoire qui alerte l'utilisateur de la coupure en faisant clignoter l'affichage de la température. En appuyant sur une touche d'information , l'utilisateur est informé de la température maximale atteinte pendant la panne de courant, et sait si les aliments surgelés ont été décongelés ou s'ils risquent d'avoir développé des bactéries dangereuses.

Les anciens réfrigérateurs utilisaient le fréon comme réfrigérant. Le fréon fait partie de la famille des CFC qui détruisent la couche d'ozone.

l’Eco2-system de SD Réfrigération et Groupe CSC

Ultimatum Media –

Notre monde suffoque!!!

Les effets de la pollution sur la santé humaine et sur l'environnement sont incalculables.

On sait cependant que si l'on ne réussit pas bientôt à freiner le réchauffement climatique, les dommages à l'environnement vont empirer au point d’être irréversibles. La santé de nos enfants, celle de leurs enfants et de leurs petits-enfants pourrait souffrir lourdement de notre immobilisme.

Alors que nos élus tardent à s'entendre et à prendre des décisions concrètes, nous devons agir. C'est exactement ce que fait l'entreprise Groupe CSC.

Grâce au Groupe CSC, le tournant vert est déjà amorcé dans l'industrie. Les réfrigérants synthétiques, qui en dommages la couche d'ozone, sont graduellement remplacés par des produits qui ne dégagent pas de gaz à effet de serre.

Groupe CSC a innové dans ce domaine. En novembre 2009, cette compagnie a installé un système de réfrigération fonctionnant au gaz « co2 » à 100% dans le supermarché IGA des Sources, à Québec. La réfrigération ET la récupération de chaleur se font en utilisant du « dioxyde de carbone ». Groupe CSC a par le fait même confondu les experts, qui croyaient impossible la récupération la chaleur en employant du « co2 ». Le « dioxyde de carbone» employé dans « l'Eco2-System »de Groupe CSC permet également de maintenir des températures stables et de dégivrer par gaz chaud.

Groupe CSC a causé toute une onde de choc dans l'industrie de la réfrigération avec l’« Eco2-System ».Cette technologie brevetée est unique car le « dioxyde de carbone »est un gaz que l'on retrouve à l'état naturel qui, contrairement à l'ammoniac est inoffensif pour la santé et l'environnement. Le « dioxyde de carbone »est éco énergétique et, détail non négligeable, il est peu coûteux.

Que ce soit dans le secteur commercial, dans l'industriel, l'agro-alimentaire, ou même pharmaceutique, l' »Eco2-System »de Groupe CSC représente la seule véritable solution aux problèmes environnementaux posés par les systèmes de réfrigération fonctionnant aux gaz synthétiques.

Groupe CSC est au cœur de l’innovation dans le secteur de la réfrigération!!!

Maritime Plaza welcomes MTL F1 Grand Prix fans

As exciting as the 2009 season has been, the notable absence of the Canadian Grand Prix put a damper on the season. Well, good news for F1 fans - especially North American fans - the Canada Grand Prix is back in 2010! When the Canadian Grand Prix comes to town, the party begins. With the combination of a great track and an exceptional nightlife, Montreal has become an annual trip for many people from all over the world.

The circuit was built in 1967 on a man-made island in the middle of the St. Lawrence River and was named in honor of Gilles Villeneuve. The Canadian Grand Prix combines a mixture of slow and fast corners and demands a lot of the engines as well as the braking system. As for entertainment, Montreal literally turns itself over to the Canadian Grand Prix each year. The city gets consumed with special events and parties during race weekend.

The annual stopover in Canada remains one of the most popular with the F1 circus. Join us in 2010 as we welcome back the Canadian Grand Prix!






Group Tidan Hotels



Our 214 rooms have been meticulously decorated to ensure your optimum well-being and comfort. Carefully designed to suit all types of travelers, our rooms offer traditional furniture and superior quality personal amenities-at a rate that is friendly to your travel budget. Our executive floors feature a goose down duvet and pillows, adding a unique touch of elegance and warmth that will provide the rejuvenating respite that you've been desiring.

Le Nouvel Hôtel accueille les fans du Grand Prix de F1 de Montréal!

Ceux qui y sont venus et qui reviennent d'une année à l'autre vous le diront : rien ne peut se comparer à l'expérience d'un Grand Prix du Canada, à ses matins d'essais libres ou ses après-midi de course au circuit Gilles-Villeneuve. On y ressent de vraies sensations. Des sons qui donnent la chair de poule, des images qui s'impriment à jamais dans la mémoire, des souvenirs impérissables, le Grand Prix du Canada en offrent toujours plein. Depuis plus de quatre décennies en sol canadien et depuis 1978 à Montréal, s'écrit une nouvelle et fascinante page de l'histoire de la Formule et du sport motorisé. C'est ainsi que s'est établi la tradition d'un événement sportif unique. Il n'y a qu'une seule façon de bien le comprendre : y être pour vivre le Grand Prix du Canada. C'est sans égal !
Laissez-vous enchanter par les services hôteliers hors-pair de notre hôtel montréalais, coté trois diamants. Le Nouvel Hôtel & Spa, c'est également le choix idéal pour une réunion d'affaires ou pour une réception somptueuse, que vous optiez pour nos salles de réception flexibles ou pour les installations du Palais des congrès, situé à deux pas.

Groupe Hôtelier Tidan

Nos suites montréalaises, aussi confortables que fonctionnelles, vous séduiront en moins de deux. Le Nouvel Hôtel & Spa vous propose également une boutique-souvenirs, un salon de coiffure professionnel, une piscine extérieure à l'eau crystalline et un centre d'affaires multifonctionnel.Nous vous invitons à parcourir notre galerie de photos et à explorer nos tarifs spéciaux et nos forfaits - bref, à découvrir ce qui fera de votre séjour chez nous une expérience inoubliable !

Récupérer l'énergie provenant des rejets thermiques

Dans l'industrie, une très grande quantité d'énergie est perdue sous forme de rejets thermiques, en raison de l'inefficacité des procédés industriels. Un problème auquel s'attaquera le deuxième volet de la chaire. "Comme l'industrie consomme 40 % de l'énergie au Canada et qu'environ seulement le quart se retrouve dans le produit final, le reste se perd dans la nature, souligne Nicolas Galanis. Pourquoi ne pas récupérer cette énergie avec un caloporteur, c'est-à-dire avec un fluide qui transporte cette chaleur vers un moteur thermique pour ensuite la convertir en électricité?" Hydro-Québec et Rio Tinto Alcan ont d'ailleurs un intérêt marqué pour ce projet.

Plusieurs secteurs bénéficieraient d'un tel procédé. "Dans les laiteries par exemple, la récupération de chaleur rejetée lors de la production du lait en poudre pourrait être valorisée, ajoute le professeur Galanis. Comme les laiteries ont besoin de chaleur pour la pasteurisation du lait, puis de froid pour sa conservation, une machine à absorption permettrait de produire du chaud et du froid selon les besoins à partir des rejets d'autres procédés."

Le Grand Prix du Canada est de retour à Montréal

Le Grand Prix du Canada est de retour à Montréal et le Nouvel Hôtel offre un rabais sur leur prix due à l’évènement!

Le Grand Prix du Canada est de retour à Montréal! Le Grand Prix accueillera les plus grands pilotes de Formule 1 à Montréal du 11 au 13 juin 2010. sur le Circuit Gilles-Villeneuve.

Après avoir célébré son 30e anniversaire au légendaire Circuit Gilles-Villeneuve en 2008, l'événement avait été annulé pour 2009, au grand dam des fanatiques de F1 de la Métropole. Mais voilà que les bonzes de la F1 en sont venus à une entente avec les responsables du côté de Montréal pour ramener le Grand Prix du Canada au calendrier

Groupe Hôtelier Tidan

Que vous soyez en voyage d'affaires ou que vous soyez convié à une réception, le luxe de nos suites, de nos lofts et de nos chambres saura vous enchanter. De plus, les groupes importants peuvent bénéficier de forfaits spéciaux - n'hésitez pas à vous renseigner lors de votre réservation!

Co2 as a Refrigerant

Even though Hydrofluoro compounds (HFC) are widely used as refrigerants because of their environment friendly nature (no damage to ozone layer), CO2 is also a popular choice as refrigerant.

Some of the advantages of CO2 as a refrigerant are:

• widely available;
• high volumetric cooling capacity and heat transfer;
• no recovery or recycling required;
• non inflammable and non toxic;
• environment friendly;
• the compressors are compact in size

Some of the difficulties is using CO2 as refrigerant are: high working pressure and large pressure difference (3 to 5 times conventional refrigerants); low theoretical efficiency with normal refrigeration systems. Hence it requiresadvanced technology compressor and refrigeration system. The hoses need to be strong as well as the evaporators and gas coolers are used instead of condensers as there is no phase change of the refrigerant. They are widely used in vending machines.

One of the difficulties of CO2 as a refrigerant is its detection and level control.

Chemical sensor elements cannot reliably measure CO2 levels. Other alternate detectors include infrared sensors.

Simulation model of a low-temperature supermarket refrigeration system.

HVAC & R Research

| October 01, 2006 | Getu, Haile-Michael; Bansal, Pradeep Kumar | COPYRIGHT 2008 American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)Copyright

This paper presents a computer simulation model of a low-temperature supermarket refrigeration system whose main components include a compressor, a display cabinet, a condenser, and a thermostatic expansion valve. The energy consumption of the system was evaluated as a function of the store relative humidity, which was measured every 16 seconds for 15 days. The model results were validated with the measurements taken from a representative in-situ supermarket in Auckland, New Zealand. The simulation results indicated that the rate of heat transfer in the evaporator was reduced by nearly 10.5 W for each 1% increase in daily average store relative humidity due to the insulating effect of the frost. The frost thickness was found to grow at 0.0354 mm for each 1% increase in the daily average store relative humidity over a 12 hour operation period between the defrost cycles. The pressure drop of the air over the evaporators increased by around 12 Pa for every 10% rise in the daily average store relative humidity.

INTRODUCTION

Supermarkets, which contain heating, cooling, and ventilation (HVAC) as well as refrigeration systems, are the most energy-consuming commercial establishments (Mei et al. 2002). According to the real measurements in the current study, the average power consumption of compressors/rack systems for both the low- and medium-temperature refrigeration systems of the supermarket amounts to roughly 20% of the total energy use. The energy consumption due to auxiliary equipment (defrosting, anti-sweat resistance heaters, display cabinet lights, and fans) and the air-conditioning system of the building are, respectively, 14% and 17%, while the remaining 49% is attributed to water, heating, and lighting systems of the establishment. Defrosting of evaporator coils is one of the most energy-consuming processes in supermarket refrigeration systems. A large amount of frost accumulation decreases the performance of the coil due to reduced rate of heat transfer and airflow. This consequently reduces the refrigerating capacity of the evaporator. Hence, frosting needs attention and should be minimized to improve the energy efficiency of the system and temperature control.

The impact of store relative humidity on refrigerated display case performance has been studied by Howell (1993a, 1993b), Orphelin et al. (1997), and Henderson and Khattar (1999), where the possible energy savings were predicted by reducing the store relative humidity and the energy penalty realized by the air-conditioning system. Among other studies by Inlow and Groll (1996), McDowell et al. (1995), Horton (2002), and Walker and Baxter (2003) on supermarket refrigeration systems, Ge and Tassou (2000) have presented a mathematical model for direct expansion supermarket refrigeration systems using TRNSYS (2001). Their display cabinet model, however, was quite restricted and used loads only due to infiltration, conduction, convection, and radiation, and the model was validated only for medium-temperature display cabinets. The simulation and the experimental work carried out so far in the supermarket industry has mainly focused on medium-temperature refrigeration systems. Further, dynamic frosting, as a result of store relative humidity, is ignored except in the medium-temperature cabinet models of Ge and Tassou (2000). Therefore, there is a need to develop a complete simulation model for low-temperature supermarket refrigeration systems, since they are most affected by the store relative humidity. This paper, therefore, presents a numerical model to investigate the performance of in-situ low-temperature display cases as a function of store relative humidity. The model includes major components of the refrigeration system, such as compressors, display cabinets, condensers, and thermostatic expansion valves. Specific correlations were used to compute frost thickness, rate of heat transfer across the evaporators, and COP. The model results were validated against the measurements taken from an in-situ supermarket located in Auckland, New Zealand, from December 1, 2004, to January 10, 2005. The model was written in a software package called Engineering Equation Solver, or EES (2004), which has built-in properties of many refrigerants. The computer model can be used as a convenient tool to accurately calculate the energy savings of the low-temperature refrigeration systems as a function of store relative humidity.

THE LOW-TEMPERATURE SUPERMARKET REFRIGERATION SYSTEM

Supermarkets have three different types of cooling systems. The first one is the air-conditioning system, whose operating temperature is roughly 5[degrees]C, which regulates the relative humidity and temperature in the occupied store. The second one is the medium-temperature refrigeration system. It has an evaporation temperature of around -8[degrees]C and provides refrigeration for fresh food such as meats, vegetables, and dairy products. The third system has an evaporation temperature down to -40[degrees]C and is called the low-temperature refrigeration system. Nowadays, there are various types of refrigeration systems, such as direct expansion/multiplex, secondary-loop, distributed, and cascade refrigeration systems. However, the direct expansion refrigeration system is the most commonly employed configuration in most supermarkets for providing refrigeration to display cabinets located in the store.

The low-temperature direct expansion refrigeration system under consideration (see Figure 1) consists of display cabinets/freezer rooms of varying geometry, multiple compressors, air-cooled condensers, thermostatic expansion valves (type DANFOSS TUA/TUAE), and evaporator pressure regulating valves (EPRVs). The function of EPRVs, as presented by Tahir and Bansal (2005), is to keep the evaporating temperatures of the respective display cabinet/freezer room at the required levels. The pressure and temperature at the suction manifold of the compressors are also determined by these valves. The dotted line enclosure shown in Figure 1 contains the evaporator assemblies, including drain points for condensate collections during defrost periods. These components in the enclosure are located within the bottom parts of the display cabinets and on the walls of the freezer rooms.

The low-temperature refrigeration system (Figure 1) consists of three major circuits that feed refrigerant R-404A to three sections of the supermarket, such as frozen food cabinets, fish/meat cabinets, and freezer rooms. The geometrical parameters and the operating temperatures of each type of cabinet and freezer room are given in Table 1.

DEVELOPMENT OF SIMULATION MODEL

The development of the simulation model for a low-temperature supermarket refrigeration system, which includes major components such as compressors, display cabinets, condensers, and thermostatic expansion valves, is discussed in the following sections.

Compressor Model

Multiple compressors (rack) in a supermarket refrigeration system are mostly of the semi-hermetic reciprocating type. If the compressor performance data are known, the compressor model may be developed based on the philosophy presented by Popovic and Shapiro (1995). Their model requires inputs such as refrigerant inlet state, outlet refrigerant pressure, clearance volume, polytropic exponents for specific refrigerants, and motor speed to calculate refrigerant mass flow rate and refrigerant.