Study of Airflow patterns in spiral blast freezers on energy utilization efficiency and freezing quality.

1. Identification

Department : Mechanical EngineeringName : Kalejaiye Adedayo OluwaseyiName of course : PhD-Mechanical EngineeringSupervisor : Prof. Zhongjie HuanCo-supervisor : Dr. Chris Enweremadu

2. Project Title

Study of Airflow patterns in spiral blast freezers on energy utilization efficiency and freezing quality.

3. Background and JustificationBackgroundWhen food products are harvested from the farm, deterioration begins to set in and shelf life of the products will be shortened. Food begins to decay and if it continues for a longer period, food quality will drop and it will not meet the safety standards for consumption anymore. Postharvest food losses can be said to be 25% of the total harvest worldwide [1]. Prevention of food deterioration and loss will require a system where food is kept at a very low temperature immediately after harvest until it gets to the final consumer at the right quality. This system is called the “cold chain system”.The Food cold chain is an integrated system in which food or any agro product is kept cold in the chilled or frozen form in an unbroken link from the initial freezing of freshly produced carcasses at the abattoirs or the farms throughout the stages of transport, storage, distribution and retail sale to the storage of frozen product at the home of the consumers. A cold chain is the specific supply chain line which is maintained at low temperature environment to maintain safety, minimise deterioration, and prevent pollution of products after harvest.

The term “cold chain” and the components thereof, refer to steps from harvest of food/agro products to consumption that extends the natural shelf life of the product by controlling temperature [3]. Typical components of a cold chain may include post-harvest handling, refrigerated transport, refrigerated storage, controlled atmosphere storage (CA), chilled or frozen processing, cold storage holding and/or distribution, retail refrigeration, institutional refrigeration, and home refrigeration. Most also continue to produce heat and in some cases ripening gases, even after harvest. Removing the heat from these products and maintaining product temperature and/or storage atmospheric composition, by chilling, refrigerated storage, CA storage or freezing reduces the rate of deterioration and extends the shelf-life of the product.[4] Diagram 1 shows the link within the cold chain system. This link should not be broken. Once it is broken, the quality of food cannot be guaranteed.

Food Harvested

Post harvest Cooling/Freezing

Refrigerated Storage

Refrigerated Transport

Cold storage Holding

Retail Refrigeration /

Display cabinets

Home Refrigeration

Diagram 1: A simple Food Cold Chain SystemThe internal heat of food and agro products must be removed immediately when harvest is done if the quality of these products is to be maintained. Most freshly harvested foods require thorough cooling immediately after harvest in order to deliver the highest quality product to the consumer. Postharvest cooling quickly removes field heat from freshly harvested products before transportation, storage, or processing and is essential for many perishable crops. This description is termed “Quick Freezing”.

Introduction to FreezingFreezing is one of the oldest and most widely used methods of food preservation, which allows preservation of taste, texture, and nutritional value in foods better than any other method. The freezing process is a combination of the beneficial effects of low temperatures at which microorganisms cannot grow, chemical reactions are reduced, and cellular metabolic reactions are delayed.

Freezing technologyFreezing has been used a long time ago as a method of preservation, and history reveals it was mostly structured by the technological developments in the process. A small quantity of ice produced without using a “natural cold” in 1755 was regarded as the first milestone in the freezing process. Ice-salt systems were first used to preserve fish and later in the late 1800’s, freezing was introduced in large-scale operations as a method of commercial preservation. Meat, fish, and butter were the main products preserved in this early example; they were frozen in storage chambers and handled as bulk commodities [13].

Refrigeration System ComponentsThe refrigeration and freezing component are the similar. Freezer component are specially designed to lower temperature of product far below 00C (for example -300C).There are five basic components of a refrigeration system, these are: Evaporator, Compressor, Condenser, Expansion Valve and Refrigerant. The refrigeration cycle can only operate successfully when each component is present within the refrigeration system as described in diagram 2 below.

Diagram 2: The Refrigeration Cycle: (Honeywell 2004)The EvaporatorThe evaporator helps is to remove unwanted heat from the product and the evaporator chamber, through the liquid refrigerant. The liquid refrigerant contained within the evaporator is boiling at a low-pressure. The level of this pressure is determined by two factors:

1. The rate at which the heat is absorbed from the product and evaporator chamber to the liquid refrigerant in the evaporator.2. The rate at which the low-pressure vapour is removed from the evaporator by the compressor.

The CompressorThe function of the compressor is to draw the low-temperature, low-pressure vapour from the evaporator through the suction line. Once it is drawn, the vapour is compressed. When the vapour is compressed the temperature increases. Therefore, the compressor transforms the vapour from a low-temperature vapour to a high-temperature vapour, and in turn increasing the pressure. The vapour is then released from the compressor in to the discharge line.

The CondenserThe condenser extracts heat from the refrigerant to the outside air. As heat has to flow from the condenser to the air, the condensation temperature must be higher than that of the air. The high-pressure vapour within the condenser is then cooled to the point where it becomes a liquid refrigerant once more, whilst retaining some heat. The liquid refrigerant then flows from the condenser in to the liquid line.

The Expansion ValveWithin the refrigeration system, the expansion valve is located at the end of the liquid line, before the evaporator. The high-pressure liquid gets to the expansion valve, while coming from the condenser. The valve then reduces the pressure of the refrigerant as it passes through the orifice, which is located inside the valve. On reducing the pressure, the temperature of the refrigerant also decreases to a level below the surrounding air. This low-pressure, low-temperature liquid is then pumped in to the evaporator.

The RefrigerantQuite a lot of refrigerants are available for refrigeration systems. The selection of a proper refrigerant is based on physical, thermodynamic, and chemical properties of the fluid. Environmental considerations are also important in refrigerant selection, since leaks within the system produce depleting effects on the atmospheric ozone layer. Some refrigerants, including halocarbons, have been banned to avoid potential hazardous effects [5]. For industrial

applications, ammonia is commonly used, while Chloroluoromethane and Tetrafluoroethane are also recommended as refrigerants.

Quick Freezers also work on the same refrigeration principle but they are designed to work up to temperature of -400C or lower based on the client’s requirement.

Freezing point of foods

Figure 1: Freezing Process for food (Mallett, 1993)As shown in figure 1 above, food is subjected to the freezing process until the appearance of the first crystal. If the material frozen is pure water, the freezing temperature will be 0 °C and, before this temperature, there will be a subcooling until the ice formation begins. In the case of foods during this stage, the temperature decreases to below freezing temperature and, with the formation of the first ice crystal, increases to freezing temperature. The second stage is the freezing period; a phase change occurs, transforming water into ice. For pure water, temperature at this stage is constant; however, it decreases slightly in foods, due to the increasing concentration of solutes in the unfrozen water portion. The last stage starts when the product temperature reaches the point where most freezable water has been converted to ice, and ends when the temperature is reduced to storage temperature.

Freezing TimeFreezing time is one of the most important parameters in the freezing process, defined as time required to lower product temperature from its initial temperature to a given temperature at its thermal centre. Freezing time depends on several factors, including the initial and final temperatures of the product and the quantity of heat removed, as well as dimensions (especially thickness) and shape of product, heat transfer process, and temperature.

The freezing time of the particular foods from the initial temperature to the final temperature can be calculated by equation 1 below [6]:

t0=ρp Δh

3 .6(T f−T ) (P0D0α +R0D0

2

λ )Eqn (1)

Where:

T f ：the initial freezing point of the product (K)

T：the freezing air temperature (K)

P0 , R0：Shape factor of product

：Characteristic dimension of product（m）

: Freezing time(h)

ρp：Specific mass of product （kg/m3）

Dh: Enthalpy difference between the initial and final temperatures of product (kJ/kg)

a: Coefficient of heat transfer rate between foodstuff and air (W/m2.K)

l：Thermal conductivity of frozen foods (W/m.K)

Freezing systemsIn selecting a freezing system initially, a cost-benefit analysis should be conducted based on three important factors: economics, functionality, and feasibility. Functional factors are mostly based on the suitability of the selected freezer for particular products. The mode of process, either in-line or batch, should be considered based on the fact that computerized systems are becoming more important for ease of handling and lowering production costs. Mechanical constraints for the freezer should also be considered since some types of freezers are not physically suitable for freezing certain products. Lastly, the feasibility of the process should be considered in terms of plant location or location of the processing area, as well as cleanability and hygienic design, and desired product quality [7].For developing countries where the freezing application is relatively new, the cost factor becomes more important than other factors due to the decreased production rates and need for lower capital investment costs.

Freezing EquipmentIndustrial equipment for freezing can be categorized in many ways, these are based on the ways the equipments are used, for example, for batch or in-line operation, heat transfer systems (air, contact, cryogenic), and product stability. The rate of heat transfer from the freezing medium to the product is important in defining the freezing time of the product. Therefore, the equipment selected for freezing process characterizes the rate of freezing.

AIR-BLAST FREEZERSAir blast freezer is one the oldest and commonly used freezing equipment because of its temperature stability and versatility when used on several product types. General, air is used as the freezing medium in the freezing design, either as still air or forced air. Freezing is accomplished by placing the food in freezing chambers. Freezing time in sharp freezers is largely dependent on the temperature of the freezing chamber and the type, initial temperature, and size of product. The advantage of the blast freezer is its versatility. It can cope with a variety of irregularly shaped products and whenever there is a wide range of shapes and sizes to be frozen, the blast freezer is the best choice.

There are several designs and arrangements for air blast freezers, these are primarily grouped in two categories depending on the mode of process, as Continuous freezers and Batch freezers. Continuous freezers are the most suitable systems for mass production of packaged products with similar freezing times, in which the product is carried through on trucks or on conveyors. The batch freezers are more flexible since a variety of products can be frozen at the same time on individual trolleys. Over-loading may be a problem for these types of freezers, thus the process requires closer supervision than continuous systems.

Tunnel freezersIn tunnel freezers, the products on trays are placed in racks or trolleys and frozen with cold air circulation inside the tunnel. For good air circulation to be possible, optimum space must be provided between layers of trolley, which allows it to be moved continuously in and out of the freezer either manually or by forklift trucks. The tunnel freezing system is suitable for all types of products, although there are some mechanical constraints which includes the requirement of high manpower for handling, cleaning, and transportation of trays.

Belt freezersBelt freezers were first designed to provide continuous product flow with the help of a wire mesh conveyor inside the blast rooms. A poor heat transfer mechanism and the mechanical problems were solved in modern belt freezers by providing a vertical airflow to force air through the product layer. Airflow has good contact with the product only when the entire product is evenly distributed over the conveyor belt. Spiral belt freezers consist of a belt that can be bent laterally around a rotating drum to maximize belt surface area in a given floor space. This type of design as in diagram 3 below, has the advantage of eliminating or minimising product damage in transfer points, especially for fragile products [12].

Diagram 3: Spiral Freezer (Seafood ITO 2010)

The Fluidised Bed FreezersThe fluidized bed freezer is a fairly recent modified type of air-blast freezer for particular product types. It consists of a bed with a perforated bottom through which cold air is blown vertically upwards. The system relies on forced cold air from beneath the conveyor belt, causing the products to suspend or float in the cold air stream. The use of fluidization has several advantages compared with other methods of freezing since the product is individually quick frozen (IQF), which is convenient for particles with a tendency to stick together [13]. Small

vegetables, prawns, shrimp, french-fried potatoes, diced meat, and fruits are some of the products now frozen with this technology.

CONTACT FREEZERSContact freezing is the one of the most efficient ways of freezing in terms of heat transfer mechanism. In the process of freezing, the product can be in direct or indirect contact with the freezing medium. For direct contact freezers, the product being frozen is fully surrounded by the freezing medium, the refrigerant, maximizing the heat transfer efficiency. For indirect contact freezers, the product is indirectly exposed to the freezing medium while in contact with the belt or plate, which is in contact with the freezing medium [12].

Immersion freezersThe immersion freezer consists of a tank or vessel with a cooled freezing media, such as glycol, glycerol, sodium chloride, calcium chloride, and mixtures of salt and sugar. The product is immersed in this solution or sprayed while it is being conveyed through the freezer, resulting in fast temperature reduction through direct heat exchange. Direct immersion of a product into a liquid refrigerant is the most rapid way of freezing since liquids have better heat conducting properties than air. The solute used in the freezing system should be safe without taste, odour, colour, or flavour, and for successful freezing, products should be greater in density than the solution.

Indirect contact freezersFor indirect contact freezer type, materials being frozen are separated from the refrigerant by a conducting material, usually a steel plate. Indirect contact freezers generally provide an efficient medium for heat transfer between product and refrigerant, although the system has some limitations, especially when used for packaged foods due to resistance of package to heat transfer.

Plate freezersThe most common type of contact freezer is the plate freezer. In this case, the product is pressed between hallow metal plates, either horizontally or vertically, with a refrigerant circulating inside the plates. Pressure is applied for good contact. This type of freezing system is only limited to regular-shaped materials or blocks like beef patties or block-shaped packaged products.

CRYOGENIC FREEZERSCryogenic freezing is a relatively new method of freezing where the food is exposed to an atmosphere below -60 °C through direct contact with liquefied gases such as nitrogen or carbon dioxide. This type of system is different from other freezing systems since it is not connected to a refrigeration plant; the refrigerants used are liquefied in large industrial installations and shipped to the food-freezing factory in pressure vessels. As such, the small size and mobility of cryogenic freezers allow for flexibility in design and efficiency of the

freezing application. Low initial investment and rather high operating costs are typical for cryogenic freezers.

Liquid Nitrogen freezersLiquid nitrogen, with a boiling temperature of -196 °C at atmospheric pressure, is a by-product of oxygen manufacture. The refrigerant is sprayed into the freezer and evaporates when leaving the spray nozzles and on contact with the products. The system is designed in a way that the refrigerant passes in counter current to the movement of the products on the belt giving high heat transfer efficiency. The refrigerant consumption is in the range of 1.2-kg refrigerant per kg of the product. Typical food products used in this system are fish fillets, seafood, fruits, and berries.

Liquid carbon dioxide freezersLiquid carbon dioxide exists as either a solid or gas when stored at atmospheric pressure. When the gas is released to the atmosphere at -70 °C, half of the gas becomes dry-ice snow and the other half stays in the form of vapour. This unusual property of liquid carbon dioxide is used in a variety of freezing systems, one of which is a prefreezing treatment before the product is exposed to nitrogen spray.

Heat transfer between food products and circulating cooled airIn food processing, there are many situations where the temperature at any point in a product is a function of time, i.e. transient heat transfer occurs. Notable examples are cooling or heating of particulate materials as in blanching and aseptic thermal processing or cooling and heating of products. Calculations of unsteady heat transfer are complicated. It is convenient to express the variables in unsteady heat transfer as dimensionless groups. The initial and boundary conditions must also be specified. In forced air cooling, both heat and mass transfer occur. Mass transfer may be in the form of evaporation of water vapour from the product or condensation of moisture on the surface.

Three cases should be considered. In the first case, the convection heat transfer coefficient is the most significant and is taken as the total heat transfer coefficient (h=hc,); in the second case, the total heat transfer coefficient is the sum of the convection and radiation heat transfer coefficients (h=hc+hr); in the third case, the total heat transfer coefficient is the sum of the convection and radiation heat transfer coefficients, and the effect of the moisture transfer on the convective heat transfer coefficient (h=hc+hr+he) [8].

The study of this heat transfer is not the focus of this research; however, the analysis of heat transfer between products and cooling air shall be done for better understanding and appreciation of this research work.

Air Circulation in cooling Chamber and Air velocityFor a well designed and properly operated freezer, the velocity of the air passing over the product must be the same everywhere in the cooling chamber. All products should be frozen almost uniformly. It is of great importance that the chamber should be designed in such away that the resistance posed by the products to the flow of air is equal for all air flow cross-sections [9]. The spaces between trays should be uniform, and the spaces below, above and on the sides of trolleys should be kept at minimum. Otherwise the air will take the path of least resistance and flow without hitting the product, rendering the freezing process inefficient.

Diagram 4: Air Flow in cooling chamber (Seafood ITO 2010)The air that is used for blast freezing is a poor conductor and has low thermal capacity, thus high air velocity is required for the freezing process. But high air velocity means more powerful and high pressure fans. Since air quantity will drop if the pressure is not sufficient, good shock freezing can not be achieved. A more powerful evaporator fan, on the other hand means that more heat is generated which must be removed by the cooling device within the chamber. While it can vary with various products, the most suitable and economical speed has been found to be between 3-6 m/s. This value denotes the velocity of air in the air passage cross section in an empty room. Higher velocities than these offer very little benefit. Assume a design of air velocity over product of around 5 m/s, in combination with good air distribution within the work area delivers the recommended air velocities over all units within the freezer.

Figure 2: Effect of Air Velocity on Freezing time (Mallett, 1993)

Air TemperatureThe air temperature within the freezer must be low enough to freeze the product in the desired time and to reduce it to the temperature it will be preserved after freezing. To give a practical example, in Great Britain -29°C frozen storage temperature and -35°C freezing temperature is recommended for fish. Each drop in air temperature causes the freezing period to shorten and the unit cost of the heat removed for freezing to increase. We can liken a cooling compressor to a submersible pump drawing water from a well. The deeper the level from which the pump draws the same quantity of water, the more power it exerts. Likewise, the lower the operating temperature of the cooling compressor, the more power and money it spends for each unit of heat it transfers from the product.

Consequently, the freezer must not be operated under lower temperatures than is required to achieve the required freezing period and final temperature conditions. Naturally, lower air temperatures than -35°C can also be used to achieve some purposes by tolerating the additional cost. These special circumstances may involve the freezing of thicker product or the necessity to abide by an inflexible schedule.

Energy consumption in Food Blast FreezingFood blast freezing is widely used by the food processing industry. Due to the great amount of heat load, the energy consumption of the freezing facilities is quite intensive, and therefore the energy saving by adopting the technologies and innovations on freezing is the one of the reason for this research work. Factors influencing energy consumption for blast freezing include the freezing air temperature and freezing air velocity, airflow patterns, heat transmission, air infiltration, and performance of the refrigeration system and its components.

JustificationThe heat that is generated by the product and the components mentioned are to be extracted by the evaporator unit of the cooling system. The evaporator fans consume substantial energy by blowing air with high velocity through the products in other to achieve quick freezing and reduce freezing time of the product at a lower temperature. However, it is shown in figure 2 that the higher the air velocity the shorter the freezing time of product, but at the same time the greater the energy consumed by the system.

Different products have different freezing temperature but operators tend to increase the velocity of the fans as a result of high demand of food products without knowing that they are as well increasing energy consumed. There is an optimum level of air velocity in which the freezing time is reasonable and the energy consumption is also at a reduced limit. This is the essence of this research.

Energy consumption is classified into residential, commercial, industrial, transport and agriculture sectors. South African households consume about 17% of South Africa’s energy; the commercial sector about 2.5% of the final energy demand; the industrial sector is the largest user of energy, consuming 68% of the electricity supply of 40 000 MW; the transport sector was 28% of the final energy demand (1995), and the agriculture was 3.8% of the final energy demand. The demand and consumption of energy are increasing at an annual rate of about 5% in South Africa [2].

The freezing is particularly energy intensive, accounting for a major portion of the energy consumed in the production of frozen foods. It was therefore surprising to see the wide variation in energy consumed, ranging from 229.6 to 935.7 kWh equivalent per ton of production [3]. It is often cited that about 50% of total energy consumption in the food industry is from refrigeration related facilities. As a result, there is a need for a research on the refrigeration facilities in the food industry in other to optimise the wide variation of energy consumed per ton of production thereby reducing the enormous energy consumption in this sector.

This research is going to study the air flow pattern relative to air velocity using Computational Fluid Dynamics (CFD) software. It will be used to determine the optimum freezing time for common frozen food products and the optimum corresponding air velocity necessary to freeze these products. The research is also going to evaluate the optimum energy consumed at different air velocity for the products. The effect of air flow pattern air velocity and freezing time on food quality will also be determined by this project. Once the optimum energy level is determined for the food products and it is in practice, energy will be saved within the food industry and the savings can be diverted to other sector of the economy.

4. a) Research Problem

It is a common practice in the food refrigeration industry for people to increase the speed of the evaporator fan in other to reduce the freezing time of food products so as to meet the high demand of food products. This practice poses a high demand on energy by the food industry and as such impact on the total energy produced by the power stations. The right combination of air velocity, air temperature and freezing time will greatly influence energy consumption by this industry.

In South Africa, 50% of the total energy consumption in the food industry is from refrigeration related facilities, so this research will try to answer the question

The air flow around the food product in the evaporation chamber is poor, hence, causing temperature heterogeneity and irregular distribution of air velocity.

The heat transfer coefficient between the food product and the cooling air is not constant hence freezing time is high.

Poor combination of freezing parameters results in inefficient energy utilisation in freezers

b) Objectives of this project.1. To determine the air flow pattern with optimum air velocity and corresponding

temperature that will freeze food product at the optimum freezing time. 2. To determine the amount of energy saved per unit mass of product at optimum air

velocity.3. To determine the quality of food product at optimum freezing time.4. To record and analyse experimental data and compare with findings within South

African frozen food industries.

Similar experiments may be performed in a number of South African food industries. The result of the experiment within the industries shall be analysed and if at optimum freezing parameters, energy is reduced and quality of the product is not compromised, then the findings may be documented and a general statement on freezing parameters that will save the country certain amount of energy in the food industry can be made. This can be implemented and energy will then be said to be utilized efficiently within the frozen food industry.

c) Research Hypothesis: A research conducted in South Africa shows that 50% of the total energy consumption in the food industry is from refrigeration related facilities, the evaporator fan is the one that consume most of the energy in the refrigeration system.

It can therefore be said hypothetically that at least half of the energy consumed by the evaporator fan may be saved by this project. If this is also cascaded to the food industries half of the energy consumed in this industry may also be saved. This will result to a significant saving of the national electricity power supply.

5. Materials and Methods

Using the computational fluid dynamics (CFD) techniques to predict the air flow pattern for fresh meat.

Design and installation of a blast freezer that will achieve a freezing temperature -400C. Work on the internal structure of chamber to enhance airflow pattern around food

product. Carryout experiments on fresh meat with different air velocity and temperature.

Determine the heat transfer between the food product and the cooling air. Evaluation of energy consumption for the system. Examine the effect of airflow pattern of food quality. Similar Experiment shall be conducted on the premises of identified frozen food

industries dealing with meat and results recorded. The experimental results (laboratory and from the industry) shall be compared with the

CFD predictions. Energy survey shall be conducted within the frozen food industries in South Africa. Evaluation of possible energy saving within the frozen food industries and results can

be communicated.

Population/Unit of AnalysisThe study is related to population of the food industry, particularly those dealing with frozen products within South Africa. The specimen or food materials shall be bought directly from the farmers or from those who are selling fresh produce. Meat for instance shall be purchased from the abattoir and seafood shall be ordered from the fishermen who get them fresh from the sea. The food materials are supplied or purchased from identified reliable suppliers and will be taken to the laboratory on the day of each experiment.

Data GatheringMeasuring instruments as mentioned above shall be used to generate data for the experiment. The air velocity shall be measured using the hot wire anemometer, the evaporator temperature shall be measured using the Infra Red thermometer, and the temperature of the food materials before and after freezing shall be measured using the digital probe thermometer or the thermocouple. Energy consumption shall be measured using the electric energy meter; weight of food material measured by weight scale, freezing time shall be taken using the stopwatch. The dimensional size of food material shall be taken by an ordinary meter rule. Data will be gathered before the experiment, during and after the experiment.

Data AnalysisGathered data from the experiment shall be analysed using two-dimensional and three dimensional figures with different parameters. Histogram and bar charts shall be used to demonstrate energy consumed by freezing different food materials and comparison of data from my experiment and the data got from the industries. The CFD software will also help to analyse and generate various airflow patterns for different velocities during the experiment.

Validity and ReliabilitySeveral readings will be taken from the instruments at a point in time and an average reading shall be taken for reliability sake. Some of the readings shall be compared with theoretical values and extreme deviation may show unreliable reading. Some of these readings and data may be double checked at the Department of Food technology of TUT for validity and reliability.

6. Time schedule for the research projectsDesign, purchase of the refrigeration equipment and installation : 16 weeksIdentify and purchase of relevant measuring instruments : 4 weeksCarrying out of experiment within TUT installed laboratory for different types of food materials and generating outputs : 52 weeksCollaboration with industries for experimental work : 24 weeksAnalysing industrial data and comparison with my experimental results : 20 weeks

Finalising experiment, collation of materials and writing of final thesis: 16 weeks

Estimated Time schedule for the research work : 132weeks

7. Support StaffTwo B Tech students will be required for this project. One will assist in the design and installation of a freezer with evaporation temperature of -400C. The other will assist in the survey of energy consumption within the food industry in South Africa.

8. BudgetThe following is an estimated budget for the project. This budget is subject to change according to the prevailing market price at the time of purchase. Budget shall be settled from the research fund available for this project.

DESCRIPTION QTY UNIT PRICE (R)

AMOUNT(R)

Complete freezer equipment 20m3 space volume and that will achieve an evaporation temperature of -400C

Lot   75,000

Construction of Spiral arrangement in the cooling chamber

1 20,000 20,000

Cost of installation of freezer equipment     12,500

Cost of buying fresh food materials including transport

Lot   10,000

Cost of buying measuring instruments Lot   12,000

Cost of constructing metal trays and trolleys 1.2 x 1.0 x 0.5m with wheels

2 800 1,600

Cost of cold room protective equipment Lot   4,000

Cost of buying CFD software 1 11,250 11,250

Cost Variable Frequency Control 1 12,500 12,500

Estimated total projects cost     178,850

9. References1) Intergovernmental organisation for the Development of Refrigeration, The role of

refrigeration in worldwide Nutrition, 5th informatory note on Refrigeration and food, Paris (France), June 2009.

2) www.info.gov.za/otherdocs/2008/nationalresponse_sa_electricity1.pdf, National response to South Africa’s electricity shortage, Feb, 2008.

3) Z. Huan, Energy saving opportunities in Food cold chain, Proceedings of International Conference of Industrial and Commercial Use of Energy, Cape Town, South Africa , 2008.

4) Chemonics international, Cold chain and storage action plans, Private sector competitiveness enhancement programme, USAID, Azerbaijan Report, May 2009

5) Honeywell control system, Introduction to refrigeration, Application Note, Published by Automation & control solution, Printed in United Kingdom, 2004

6) Z. Huan, Matching of freezing parameters on energy savings for blasting freezers, International refrigeration conference, Czech, 2011.

7) W.A Johnson et al, Freezing and Refrigerated storage in fisheries, FAO corporate document repository, Fisheries Technical Paper No. 340, ISBN, Aberdeen, 1994

8) Ibrahim Dincer, Transient Heat Transfer Analysis in air cooling of individual spherical products, Journal of Food Engineering, Volume 26 Issue 4, pages 453-467 1995.

9) Naci Sahin, Blast Freezing Application in a Convective Room, Friterms Rev0.0, Turkey, July 2004

10) Seafood ITO, Freeze Seafood Products, A training workbook for unit standards 6202 V3, Wellington, 2010.

11)Gustavo V. Barbosa-Cánovas et al, Freezing of fruits and vegetables An agribusiness alternative for rural and semi-rural areas, FAO Agricultural Service Bulletin Vol 158, ISBN, Rome, 2005.

12) Mallett C.P, Frozen Food Technology, Chapman and Hall, London, 199313) Persson, P.O and Lohndal, G., Freezing Technology, Frozen Food Technology,

Chapman and Hall, London, 1993