Leeds Metropolitan University
School of Built Environment and Engineering
BSc (hons) Building Services Engineering
Module Title: Dissertation
Assignment Name: Dissertation
Dissertation Title: Mega-Supermarket optimal energy distribution design
Student Name: Mak Tsz Ho
Student No.: 77146690
Nowadays, the most of people will go supermarket to purchase their Daily necessities and food. Supermarket is quite convenient for modern people. There have about two thousands supermarket in Hong Kong. In the supermarket, we can find many different Areas, for example, frozen food area, wine area, cold drink area, fruit area, delicatessen area and Drug area. Different Areas have different requirement for air conditioning. Also, in the supermarket have many people flow. We need to design a comfort environment to those people in the supermarket. In the supermarket, we also need to design an enough lighting environment for those consumers. Sufficient lighting can give the consumers a good image. Base on above several points, we can estimate the energy consumption for HVAC and lighting must be quite large in the supermarkets.
The modern mega supermarket is a high-volume sales outlet with maximum inventory turnover. A new category of supermarkets incorporates a supermarket section and a general dry goods section in one shop. Almost half of supermarket is of perishable foods including fresh meats requiring refrigeration. Dairy products, frozen foods, perishable produce, frozen desserts and ice cream, all specialty items such as bakery and prepared meals and deli products. These foods are displayed in flexible storage, handling, and display apparatus. Many supermarkets incorporate food service operations that prepare the food. Refrigerant piping connects these to condensers and compressors. These equipments are normally located outside of the supermarket area, either on the roof Food products or in machine rooms must be kept at suitable temperatures during storage, transportation, processing, and during display. The food stores back room is both a warehouses and a processing plants distribution point that includes refrigerated rooms. Refrigeration-related areas must be considering during construction because of the interaction between the mega supermarket’s refrigeration equipment and itsenvironment.
In this dissertation, we will go through the different kind of energy consumption and find the way how to decrease the energy consumptions and optimal energy distribution design in Mega-supermarket.
Because supermarkets operate on the narrow profit margin, energy costs play a crucial role in the supermarket economics and competitiveness. In many cases the annual energy costs for a supermarket equals or exceeds the sales profit. A supermarkets annual energy costs depend heavily on the refrigeration systems energy use. The energy systems operations are sensitive to the impact of various food and energy codes.
The final target of optimal energy distribution design is energy savings. Energy Saving means utilizing the minimum amount of energy for heating, cooling, equipment and lighting that is required to maintain comfort conditions in a building. Improvements have been made in insulation, plant, lighting and controls and these are significant features that help towards achieving an energy efficient building. At this stage it is important to know what is meant by Energy saving.
In recent years, the use of energy in buildings has increased due to the growing demand in energy used for heating and cooling in buildings. Buildings operated could not without energy. Improvements have been made in insulation, plant, lighting and controls and these are significant features that help towards achieving an energy efficient building. At this stage it is important to know what is meant by Energy saving.
The amount of energy consumed varies depending on the design of the fabric of the building and its systems and how they are operated. The heating and cooling systems consume the most energy in a building, however controls such as programmable thermostats and building energy management systems can significantly reduce the energy use of these systems. Some buildings also use zone heating and cooling systems, which can reduce heating and cooling in the unused areas of a building. In commercial buildings, integrated space and water heating systems can provide the best approach to energy-efficient heating.
In this dissertation, we would go to some mega supermarkets in Hong Kong to survey their energy system and their characteristic of optimal energy distribution design. The surveyed mega supermarket as show as below:
1: Jasons Food and living — ( B1, Hysan Place, Causeway Bay, Hong Kong)
2: Taste Supermarket (Festival Walk, Yau Yat Chuen, Kowloon Tong, Kowloon, Hong Kong)
1. Jasons Food & Living
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In this mega supermarket, they have cool drink counter and cold food counter in the nearest place.
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Also, they have a place for wine and alcohol.
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The refrigerator is place near the wine.
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In the corridor, they have a hot food counter.
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The dry goods is place together.
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In Jasons food and living, we can see that they have plan to their goods, foods and drinks. They separated their goods by two principles:
1. Hot goods and colds goods are separated into two zone.
For hot goods and foods, the have locate a area for those things. For example, have a corridor to sell their hot foods. Also, they have cool drink counter and cold food counter in the nearest place. This arrangement can save energy because hot goods and cold goods have different requirement to keep their product freshest, same place use same criteria can keep the use of energy stable, so that energy can save.
2. The humidity is other principle for this supermarket.
For those goods which need to keep low humidity are place together, such as dry goods. Also, some goods like wine need to keep a constant humidity which is place together. This principle keeps use less energy to control humidity anywhere in mega-supermarket.
2: Taste Supermarket
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The frozen goods are place together. We can see all the refrigerator is place together..0/msohtmlclip1/01/clip_image014.jpg”>
The wine place in a corner to place which is separate with others goods.
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The hot foods is place in the heater and is at the corner of the supermarket.
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The dry goods is place together.
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In Taste supermarket, we can see that they have plan to their goods, foods and drinks. They separated their goods by two principles:
1. Hot goods and colds goods are separated into two zone.
For hot goods and foods, the have locate an area for those things. For example, have a corridor to sell their hot foods. Also, they have cool drink counter and cold food counter in the nearest place. This arrangement can save energy because hot goods and cold goods have different requirement to keep their product freshest, same place use same criteria can keep the use of energy stable, so that energy can save.
2. The humidity is other principle for this supermarket.
For those goods which need to keep low humidity are place together, such as dry goods. Also, some goods like wine need to keep a constant humidity which is place together. This principle keeps use less energy to control humidity anywhere in mega-supermarket.
Literature Review:
1. Analysis of energy savings in a supermarket refrigeration/HVAC system
Ammar Bahman, Luis Rosario and Muhammad M. Rahman
Source: Internet
The paper is about refrigeration/HVAC system energy consumption in a typical food retail store to show the effects of indoor area conditions. Refrigerated display case is normally rated at a store environment of 23°C (74°F) and a relative humidity of 54%. If the store can be maintain at lower relative humidity, the quantities of refrigeration energy, defrost energy, and anti-sweat heater energy could be saved. Calculations have done for a typical day in a typical store for each month of the year using the climate data for Tampa, Florida. This result show relative humidity in a 24h variation in the store. Using these hourly values of relative humidity for a typical 24hday, relative humidity of the store distribution for a full year was calculated. The relative humidity of annual average supermarket was found to be 51.1%. It is shown that for a 5% reduction of relative humidity in store, 9.35% reduction of the display case refrigeration load, and that results in total store energy load reduction of 4.94%. The results are compared to available experimental data and find to have a good agreement.
In this paper, we can see that control a constant low humidity can save energy and the total store energy load can be reduce. This papers example shows that high humidity is need to use more energy to keep the indoor space conditions. In this paper, we can learn that humidity is important to keep the temperature in an indoor area. If the mega-supermarket keep the humidity lower, the energy load will be reduce. This idea is important for this dissertation because our topic is Mega-Supermarket optimal energy distribution design. This paper can inspire us to use low humidity to save energy in mega-supermarket.
2. Analysis on energy saving potential of integrated supermarket HVAC and refrigeration systems using multiple subcoolers
Liang Yanga, Chun-Lu Zhang
Source: Internet
The paper presents a model based analysis on the energy save potential of mega-supermarket refrigeration systems and HVAC (heating, ventilating, and air-conditioning) using multiple sub-coolers among the high-temperature HVAC system, the medium-temperature refrigeration system, and the low-temperature refrigeration system. The principles of energy reduction are to have the higher coefficients of performance (COP) system produce more cooling capacity to reduce the power consumption of the lower COP system or increase the cooling capacity. The sub-cooler could be placed between the high-temperature and low-temperature systems, between the medium temperature and low temperature systems, and between the high temperature and medium temperature systems. All integration conditions of adding one, two and three sub-coolers have been searched. The energy saving potential changes with the load ratio between low-, medium- and high-temperature systems, COP of three systems, and the on-off duty time of HVAC system. The optimal sequence of adding sub-coolers is also proposed.
This paper say that using multiple sub-coolers can be reduce energy and have the higher coefficient of performance system generate more cooling capacity to increase the cooling capacity or reduce the power consumption of the lower COP system. We can use the multiple sub-coolers to respectively different temperature systems (high , middle & low temperature). This paper is useful for our topic, we can use this method to achieve energy saving in mega supermarket.
3. Air Flow Distribution in the Sales Area of a Supermarket
Xiumu Fang Chuanliang Song Jianing Zhao Zhaojun Wang
Source: Internet
In amega-supermarket many different of goods are displayed in amegasupermarket, which have their own particularities. The consumer flow rates are great and the types of shelved goods varies significantly, thereby effect the objects that generate the demands of air temperature, heat, air humidity and velocity in different zones. In this paper, the results are presented of a study of a sales area of a supermarket in Harbin, including air velocity, air temperature and humidity. According to the assessment index of air flow distribution (EDT, energy coefficient of utilization, ADPI, coefficient of ununiformity ,temperature efficiency and so on), the experimental dataare analyzed. Suggestion for air conditioning system designis presented in this paper. The rationality of airflow distribution was thencalculated.
In this paper, we can know that the important ofAir Flow Distribution in a mega supermarket. It help us to find that the air flow would be effect the energy. If we need to do the optimal energy distribution in supermarket, air flow is the one of important idea.
4.Supermarket Refrigeration System with Completely Secondary Loops
Vasile Minea Ph.D., Member ASHRAE
Source: ASHRAE Journal
The advanced system presented in this paper involves secondary fluid loops on both refrigerating and condensing sides, and heat recovery with brine-to-air heat pumps and passive heat exchangers. This integrated concept has a considerable potential to reduce combined refrigeration and HVAC energy use in supermarkets located in northern climates compared to multiplex refrigeration systems with more conventional heat recovery approaches. It also may reduce up to 70% of the quantity of primary refrigerant required.
The completely secondary loop supermarket refrigeration concept is distinguished by its simple configuration. It uses standard refrigeration components, is not difficult to operate and control, and has less refrigeration valves and fittings than most of conventional systems. However, this this concept represents a significant technological change, so trained refrigeration technicians and operators are needed.
The total quantity of the primary refrigerants (R-507) was reduced by 62% compared to baseline multiplex refrigeration systems. By optimizing refrigeration piping diameters and lengths,and reducing the liquid receivers’ capacities, the primary refrigerant charge can be reduced, compared to multiplex systems up to 71%. The heat recovery method with brine to air heat pump on the lower temperature rejection loop provided efficient space heating because of at the operating conditions in a cold climate winter the heat pumps’ high coefficients of performance (4.6). The backup electrical coil of the central HVAC unit has never operated during small quantities of heat were rejected outdoors during the winter and the winter for makeup outdoor air preheating. Both medium refrigeration and low refrigeration zones have been operated with stable parameters, while the thermodynamic cycles of primary refrigerant are normal according to thermodynamic refrigeration rule. These performance is attributable to the secondary fluids of thermal inertia, to the correct adjustments of secondary fluid flow and of primary refrigerant charges and to a rate, simple and efficient control strategy. The main heat exchangers (, sub-coolers, desuper- heaters, evaporators and condensers) have been designed correctlyand have been operated according to the state of the art of heat transfer. Even though the new system includes secondary fluid circulating pumps and refrigerant to brine evaporators, and thus, is subject to additional energy consumptions and heat transfer irreversibility, the specific annual energy consumption of the new mega supermarket (841 kWh/m2/ year) seems to be in the same level of magnitude and lower compared to Canadian conventional multiplex refrigeration systems with de-superheating coils and fossil fuels as backup energy sources. The main component of the medium- and low-temperature refrigeration zones (secondary fluid pumps , liquid coolers fans, and compressors) have assumed 31.2% of the supermarket’s total annual energy consumption. Small leakage of freezing secondary fluid has been caused by the poor quality the initially selected solenoid and ball valves, and of soldering materials. Two years