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The performance of a multistage centrifugal compressor is highly influenced by the ambient conditions, especially during the summer seasons; their capacity shrinks and thus the power requirement for compression will increase. The prime cause of these constraints is the interstage cooling limitations. This study simulates various suction conditions of a multistage compressor on Aspen HYSYS® and suggests its debottlenecking by making the suction temperatures comparable to winter seasons. This is achieved by installing an additional exchanger at the downstream of each interstage cooler, cooling down the gas further by using absorption refrigeration chillers. These chillers are powered up by the waste heat recovered from the exhaust steam coming from the prime mover, steam turbine, of the same compressor. This modification will save a considerable amount of power (663 kW), net savings (Gross Savings – OPEX: 72 289 $/y), and reduce the carbon footprint (954 ton/y) of the overall process.

Chillers are an important component of the heating ventilation, and air conditioning industry which is one of the largest energy consuming sectors. Magnetic bearing systems have been adopted in the chiller industry to improve compressor efficiency. A life cycle assessment (LCA) of greenhouse gas emissions of magnetic bearing chillers, with a particular focus on the manufacturing stage, has not previously been conducted. This study evaluated global warming potentials of two water chiller systems, an oil lubricated bearing system, and a magnetic bearing system, over their life cycle stages including raw material extraction, manufacturing, transportation, use, and the end of life. The standard ISO 14044 LCA framework was employed to assess the two 500‐ton cooling capacity chillers from a US chiller manufacturing company. Uncertainty analysis was conducted on carbon emission factors from the research literature and sensitivity analysis was conducted on key variables including power mix emission factor, chiller efficiency, and transportation method. The results show that magnetic bearing systems perform better with respect to life cycle GHG emissions. For a general water chiller system life cycle, over 90% of the emissions result from electricity consumption during the use stage with the next largest emissions arising from material extraction and manufacturing. While the material use and manufacturing GHG emissions are similar in the two systems, due to its higher compressor efficiency the magnetic bearing system generates fewer GHG emissions in the use stage. Sensitivity analysis was conducted on electricity mix, non‐standard part load value (NPLV), and transportation method. When the factor values were varied with 5% steps to ±25%, the chiller efficiency and power mix emission factors behaved in similar ways in improving life cycle GHG emissions. NPLV, however, becomes more challenging to improve despite the long history of research on compressor efficiency. This study not only provides analytical data at the product level as to how much GHG emissions can be reduced by improving compressor efficiency and incorporating clean energy, but also provides life cycle GHG inventory data for different end of life and transportation strategies.

A CCHP-ORC system consisting of a MGT, an ORC and an absorption refrigeration chiller was proposed in this study. A verified simulation model based on specific mass, energy conservation and exergy destruction was built. Thermodynamic analysis was applied to the system. A parametric study was carried out to investigate the impacts of the ORC's evaporating temperature and, turbine efficiency, and the ARC's generating temperature on the system's performance. Six different organic working fluids (R141b, Toluene, D4, n-Octane, n-Heptane and MM) were selected in this study, and their impact on the system's performance was also analyzed. The results showed that the CCHP-ORC system's primary energy efficiency and exergy efficiency could reach a maximum of 76.89% and 54.95% respectively, with toluene as the organic working fluid. The MGT accounted for a large part of exergy destruction in both the CCHP-ORC and reference system. Compared to the reference system, the total exergy destruction of the CCHP-ORC system decreased, for all six organic working fluids. The main exergy reduction occurred in the GEN, ABS and DHW. A T-Q diagram method was conducted to analyse the heat transfer process in the CCHP-ORC and reference system. The results showed that the CCHP-ORC system can significantly reduce the mean heat transfer temperature difference in the heat transfer process, which helps to decrease the exergy destruction in GEN, and improves the system's exergy efficiency. Hence, it is beneficial for the system's efficiency and exergy destruction to introduce ORC as a middle cycle into the CCHP system. © 2017 American Institute of Chemical Engineers Environ Prog, 2017

Summary In this study, we present a novel teaching-learning-based optimization (TLBO) algorithm for solving the optimal chiller loading problem. The proposed algorithm uses a novel integer-based encoding and decoding mechanism that is efficient and easy to implement. The teaching phase can improve the quality of learning process and thus enhance the exploitation ability. In addition, a well-designed learning phase procedure is developed to enhance the learning process between one another in the population. A novel exploration and self-learning procedures are embedded in the proposed TLBO algorithm, which can enhance the exploitation and exploration capabilities. The proposed algorithm is tested on several well-known case studies and compared with several efficient algorithms. From the experimental comparisons, the efficient performance of the proposed TLBO is verified.

Forecasting the ecological consequences of a changing climate requires a range of approaches, including the use of mesocosms in which multiple physical and chemical parameters can be manipulated and the response of interacting organisms quantified. Here, we describe the design and evaluate the performance of a facility incorporating large mesocosms that can contain diverse biological assemblages within which CO2 and temperature can be manipulated. The key infrastructure is: 15 covered mesocosms each with a maximum water volume of 2300 L, a gas mixer containing two mass flow controllers to produce CO2-enriched air and an individual heater/chiller unit for each treatment mesocosm to independently regulate temperature. Our results report an initial proof-of-concept experiment (total of 100 d duration) in which we constructed communities of biota that characterise temperate Australian kelp forests (i.e., kelp, their key competitors and herbivores) and then undertook procedures designed to reproduce CO2 and temperature conditions forecasted for the year 2100 (target differences in midday means: 0.15 pH units, 2.5°C). The system achieved the intended environmental conditions, with CO2 and temperature in treatment enclosures consistently different from the controls (mean midday treatment effect ± SE; 0.15 ± 0.01 pH units and 2.6 ± 0.1°C, respectively), yet still tracking their diurnal fluctuations. The reliability of the facility over the experimental period indicates it is a robust and accurate tool that can mimic intended scenarios of CO2 and temperature change, facilitating the study of the influence of these factors on marine organisms and their interactions.

Optimal design of an energy storage tank system is presented in this study. Total annual cost is considered as the objective. To minimize the total annual cost, 24 design parameters including the operational strategy of the chiller in each hour during a sample day are selected. A Particle Swarm Optimization (PSO) algorithm is used for three different strategies including partial storage (PS), full storage (FS), and variable storage (VS), separately. In addition, this procedure is performed for both electrical and absorption chillers. There was a 25.21% and 13.80% improvement in total annual cost observed in the VS strategy compared with the PS and FS strategies, respectively, in the case of an electrical chiller. Furthermore, 23.47% and 8.01% improvement in total annual cost is observed in the VS strategy compared with the PS and FS strategies, respectively, in the case of an absorption chiller. Moreover, the electrical chiller was found to be more suitable in this study but no sensible difference is observed in the FS strategy. Finally the optimum results of the PSO algorithm is compared with the Genetic Algorithm (GA) and differences are reported.

Conventional chilling methods such as forced air (FA) and water immersion (WI) are used in the industry to chill poultry carcasses from approximately 40 to 4C, which is essential to improve safety. Besides both processes, a combined method (CO) of WI and FA has been reported in the literature. The objective of this investigation was to compare the chilling of poultry carcasses by FA, WI and CO using an experimental apparatus specially designed for this purpose. Time-temperature evolutions of pectoral muscle and carcass mass variations during the chilling processes were determined under different chilling conditions, comprising different air velocities and relative humidities (RH). The results showed that it is possible to reduce the water loss (approximately 50%) and chilling time (reduction between 14.5 and 1.5%) of FA process using CO process. Air velocity and RH ranges can be varied to take advantage of evaporative chilling and to reduce the carcasses water loss. Practical Applications In the factories, poultry carcasses are chilled from approximately 40 to 4C by water immersion, which is crucial to ensure safe products. However, air chilling (AC) has been often used for safety reason and due to the limited availability of water. On the contrary, wetting the carcasses avoids excessive moisture loss in air chillers, whereas the evaporation of the water adhered to the carcass surface may assist the chilling process. The present paper evaluates the effectiveness of AC and of a combined chilling method (CC) (AC combined with water immersion chilling) of poultry carcasses at different relative humidity and air velocities. The results showed that the CC process was shorter and reduced carcasses weight loss compared with the AC process.

A multivariable fuzzy controller was developed and implemented for the regulation of the secondary fluid temperature in a chiller using both the rotation frequencies of the pump and the compressor as manipulated variables. Its performance was measured using the integral of time-weighted absolute error (ITAE) index and the energy consumption. The proposed control strategy proved able to adequately control the chiller in all experiments. For comparison purposes, similar experiments were carried out with fuzzy control strategies in which only one variable was manipulated at a time. Comparing the performance of the proposed controllers with the fuzzy single input–single output controllers for regulatory control, a mean percentage reduction of at least 88.5% was observed in the ITAE. Good results were also observed in control effort and energy consumption. Besides, the implementation of the control strategy was quite simple. Practical Applications Refrigeration systems are of fundamental importance for food conservation. Besides, to maintain the temperature into a narrow range needs an efficient control system and implies energy consumption and equipment wear. The use of a fuzzy controller with two manipulated variables to regulate the secondary fluid temperature has proved to be an efficient control configuration. Desirable characteristics like small or no overshoot, reduced control effort were achieved by the proposed multivariable fuzzy controller. Therefore, this proposed strategy is a valuable alternative to control processes that require strict variability or long periods of operation without stopping.

In this work, an artificial neural network (ANN) was used to predict the final temperature of chicken carcasses in an industrial scale. For this purpose, temperatures of chicken carcasses were obtained in a slaughterhouse at the end of the cooling process. The variables considered to influence the temperature of carcasses were average carcass weight, prechiller and chillers velocities, prechiller and chillers average temperatures, the absence or presence of bubbles in prechiller and chiller and bubbles intensity, which were considered as input for the ANN. For training and validation of the feed forward neural network, the above inputs were combined to minimize the weighted sum of the squares of the residues, being tested 10 transfer functions, three training algorithms and two different architectures. The best result was obtained using an ANN composed of two hidden layer (10 nodes in each layer), radial bias as transfer function and gradient descent backpropagation algorithm for training. Using this architecture, the regression coefficient was 0.9265. Even with many variables affecting the industrial cooling process of the chicken carcasses, the ANN developed showed satisfactory fitting of the final temperature of chicken carcasses. This model can be further used for optimization purposes, improving the process quality of chicken carcasses as well as process profitability. Practical Application The model used in this study can be further used for control and optimization purposes, improving the process quality of chicken carcasses as well as process profitability.

Optimization and a cost-oriented analysis, including the capital and energy-of-compression costs, were performed to compare propane- and ammonia-refrigeration economizer cycles with and without presaturators. The simulation and optimization to minimize the cost were performed by using the HYSYS simulator and the Peng–Robinson equation of state was used for the thermodynamic model. Different chiller temperatures and duties were considered. The simulation and optimization results show the limitations of simplified formulas in determining properly the optimum intermediate compression pressure in refrigeration economizer cycles. The results also show that having a presaturator lowers the cost of ammonia refrigeration cycles and enhances costs in propane loops. Among all, ammonia cycles with presaturators were found to offer the lowest cost. The exergy and economic analyses show quite similar distributions of the lost work and cost in the different components of the refrigeration loops. Ammonia refrigeration cycles with presaturators offer the lowest lost work and the highest coefficient of performance. However, the chiller temperatures are limited to approximately −33.3 °C (−28 °F) in the case of ammonia cycles whereas they can be as low as −41.7 °C (−43 °F) in propane loops.

Combined power and refrigeration cycles have been explored for improving their overall energy conversion efficiency and decreasing the cost of energy produced. Bottoming cycles can be used to recover the waste heat or exhaust heat of gas turbines and conventional steam Rankine cycles and convert it to work and/or refrigeration. In most applications, refrigeration is the more expensive product than power because it requires refrigeration equipment as well as power to produce conventional refrigeration. Therefore, the additional output of refrigeration by the combined cycle provides greater benefit than conventional power systems. This paper presents a review of combined power and cooling cycles for effective utilization of heat sources. (C) 2013 John Wiley & Sons, Ltd.

This article investigates and recommends design improvements of cooling coil geometry contributes for a central cooling system by using a simulation-optimization approach. First, theoretical–empirical system models including mechanistic relations between components are developed. An actual central cooling plant of a commercial building in the hot and dry climate condition is used for experimentation and data collection. Available experimental results were compared to predicted results to validate the model. An algorithm was created in a transient system simulation program to predict the best design. Then different new designs for cooling coil were constructed to evaluate the potential of design improvements. Afterwards, the computer model was used to predict how changes in cooling coil geometry would affect the building environment conditions and the energy consumption of heating, ventilating, and air-conditioning components. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 1209–1216, 2013

Sorption cooling technologies are well known as energy efficient cooling supplying apparatuses where heat as driving energy is used from waste heat sources, trigeneration systems (engines), solar thermal plants, etc. Especially in the air-conditioning business often a strong correlation exists between insolation and cooling requirement. Therefore, the interest in solar cooling systems prevails since several decades. Some hundred systems have been installed all over the world and operate, some satisfactorily and some others not. However, no really cost-competitive system for widespread application exists. A step forward can only be expected by innovative design of collectors or chillers, by improved system integration and enhanced control strategies, or by expanded application, e.g., the use as a heat pump in the heating period as well. The state of the art was reported several times. Here three important topics are highlighted: the role of collector and process development, the primary energy demand (in combination with the conventional back-up system and auxiliary energy needs), and the role of the double use of the system during summer and winter time (i.e. collectors for both heat and cold, sorption apparatus as chiller and heat pump). The paper is focusing on solar air conditioning rather than solar refrigeration.

In this study a residential community in Phoenix was selected as the basis to develop design methods for a residential microgrid. A microgrid model was built using computer based software. Photovoltaic (PV) modules, microturbines, and fuel cells were chosen as the distributed energy resources (DERs) for the model. The optimal residential microgrid system configuration was sorted out according to the least net present cost (NPC), and the least cost of energy (COE) of the designed microgrid system. The results indicate that the COE of the designed microgrid in island mode is expensive, although it is more environmentally friendly compared to the grid. The purpose of combined cooling, heating, and power (CCHP) is achieved by utilizing the exhaust heat from microturbines to provide daily hot water consumption while cooling demand is achieved through the connection of adsorption chillers to microturbines. Sensitivity analysis shows that natural gas price escalation and price reduction of DERs significantly impact COE and NPC. Copyright © 2010 John Wiley & Sons, Ltd.

The adsorption of water vapor in the highly porous metal-organic framework (MOF) of 3D-[Cr3F(H2O)2O(bdc)3·~25H2O] (MIL-101) (bdc = benzene-1,4-dicarboxylate, terephthalate) of up to 1 g of water per gram of sorbent material (between 140 °C and 40 °C under a water vapor pressure of 5.6 kPa) together with the stability over several cycles makes MIL-101 the most promising material, so far, for heat transformation applications like thermally driven heat pumps or adsorption chillers.

Absorption refrigeration is gaining increasing attention in industrial facilities to use process heat for partially or completely driving a cooling cycle. This paper introduces a systematic approach to the design of absorption refrigeration systems for industrial processes. Three sources of energy are considered to drive absorption refrigerators: excess process heat, solar energy, and fossil fuels. To handle the dynamic nature of solar energy, hot water tanks are used for energy storage and dispatch. Thermal pinch analysis is performed to determine the amount of available excess heat and the required refrigeration duty. Next, a multiperiod optimization formulation is developed for the entire system. The procedure determines the optimal mix of energy forms (solar versus fossil) and the dynamic operation of the system. Three case studies are solved to demonstrate the effectiveness and applicability of the devised procedure.

The power generating efficiency of solid oxide fuel cell (SOFC) and gas turbine combined cycle is fairly high. However, the exhaust gas temperature of the combined cycle is still high, about 300°C. Thus, it should be recovered for energy saving, for example, by absorption chiller. The energy demand for refrigeration cooling is recently increasing year by year in Japan. We propose here a cogeneration system by series connection of SOFC, gas turbine and LiBr absorption chiller to convert the exhaust heat to the cooling heat. As a result of cycle analysis of the combined system with 500-kW-class SOFC, the bottoming single-effect absorption chiller can produce a refrigerating capacity of about 120 kW, and the double-effect absorption chiller can produce a little higher refrigerating capacity of about 130 kW without any additional fuel. But the double-effect absorption chiller became more expensive and complex than the single-effect chiller. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(1): 49– 55, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20578

Summary The thermal diffusivity of potato and the apparent heat transfer coefficients (h) in a conduction chiller and in a combination oven at 85, 90 and 95°C and vario-steaming mode were determined experimentally. Based on K-S tests and assumption, the variabilities of all six parameters (thermal diffusivity, h values for heating and cooling, initial food temperature, process medium temperatures and z value) were represented by normal distribution only (model A) or by both normal and gamma distributions (model B). The mean P70 values and their 95% confidence intervals for three oven temperatures, estimated from experimental temperature histories, were 1510 ± 101, 1590 ± 131 and 1590 ± 170 min (for each oven temperature, n= 100) respectively. Good agreement was obtained between these estimations and those predicted using the Monte Carlo procedure and models A and B.

Summary A survey has been made of the effects of process parameters on the microbiological contamination of spin-chiller waters at five poultry process plants in the UK. Water samples, taken at hourly intervals, from both the first and second chillers were examined bacteriologically and for the levels of residual chlorine pH value and turbidity. Water usage was also monitored. In one process line comparison was made of the effect of substantial modification to the process plant resulting in changes in both water usage and chlorination levels. The colony counts of presumptive coliform bacteria and other bacteria were reduced generally to 41/kg carcass weight) was combined with high total residual chlorine (30–50 ppm). Higher numbers of bacteria (normally 41/kg) was combined with low residual total chlorine (< 5 ppm) or when low water usage (< 1 1/kg) was combined with moderate levels of residual chlorine (7–16 ppm). The signifiance of the results is discussed with reference to the hygienic operation of spin-chillers.

This paper describes an introduction of research and development activities on steam cooling in gas turbines at elevated temperature of 1500 C and 1700 C level, partially including those on water cooling. Descriptions of a new cooling system that employs heat pipes are also made. From the view point of heat transfer, its promising applicability is shown with experimental data and engine performance numerical evaluation.

Poultry carcasses are chilled in water to lower the temperature rapidly. Water quality in the chiller is maintained by overflow and freshwater makeup. This in-plant study evaluated reconditioning of chiller overflow by ultrafiltration for reuse in place of freshwater makeup. Trials with hollow fiber and spiral polymeric membrane modules were conducted to verify microbial rejection and to obtain flux characteristics. Microbial challenge trials conducted by using chiller overflow with artificially enhanced microbial levels reduced microbial counts by more than 5.4 log cycles. The rejection of chemical oxygen demand was over 73% and the reduction in turbidity was over 99.2%. These results verified that ultrafiltration produces water acceptable for reuse in the chiller to partially replace freshwater makeup. Concentration scans, pressure scans, velocity scans and time scans produced satisfactory permeate fluxes. Membranes cleaned easily after the trials. A 380-L/min (100-gal/min) spiral ultrafiltration system was designed assuming a 34-L/m2h (20 gfd) average permeate flux based on flux characteristics observed during the trials. Economic assessment of the system operation indicated a 2.4-year simple payback with possibilities for further improvement.

Simplified analytical models are developed for evaluating the thermal performance of closed-wet cooling towers (CWCTs) for use with chilled ceilings in cooling of buildings. Two methods of simplification are used with regard to the temperature of spray water inside the tower. The results obtained from these models for a prototype cooling tower are very close to experimental measurements. The thermal performance of the cooling tower is evaluated under nominal conditions. The results show that the maximum difference in the calculated cooling water heat or air sensible heat between the two simplified methods and a general computational model is less than 3%. The analytical model distribution of the sensible heat along the tower is then incorporated with computational fluid dynamics (CFD) to assess the thermal performance of the tower. It is found that CFD results agree well with the analytical results when the air flow is simulated with air supply from the bottom of the tower, which represents a uniform air flow. CFD shows the importance of the uniform distribution of air and spray water to achieve optimum design. Copyright © 2002 John Wiley & Sons, Ltd.

This paper reviews an inexpensive statistical-sampling methodology that can be used to determine the attrition rates of certain types of shipboard equipment. The methodology relies on surveys that are conducted in conjunction with regularly scheduled ship visits over a period of time and a statistical analysis of the survey results. The statistical technique allows for reasonably accurate estimates to be made of attrition rates. The specific example cited in this paper is related to galley-type refrigeration equipment, such as salad chillers, beverage dispensers, et cetera. In the case of galley-type refrigeration equipment, the Navy needs to know whether the Fleet's inventory of equipment relying on Class I Ozone-Depleting Substances (ODSs) will be replaced through natural attrition by the end of fiscal year (FY) 2005, at which time supplies of ODS-based refrigerants will no longer be available for use by ship galleys. This paper outlines the process used to gather data, the analysis of the data, and concludes that the Navy's inventory of galley equipment using Class I ODSs will be replaced through natural attrition by the end of FY05. The methodology reviewed by this paper has wider applications. For various types of shipboard equipment, the methodology can also be used to estimate with reasonable accuracy life expectancies, configurations, conditions, and other items of interest.

The effects of model and process parameters on the predicted chilling time and mass loss of a beef carcass during chilling were studied by validated computer simulation. The effects of surface heat transfer coefficient, and thermal diffusivities of fat and muscle on the chilling time were significant as well as the effects of surface heat transfer and mass transfer coefficients on mass loss. However, the effects of moisture diffusivities on the chilling time and mass loss were insignificant. All of the process parameters significantly affected mass loss and chilling time. A decrease in relative humidity or an increase in air velocity or ambient temperature increased mass loss. An increase in air velocity or a decrease in ambient temperature decreased the chilling time. Based on the parametric analysis of the process parameters, air velocity in the chiller should be less than 1 m/s and the relative humidity of the chiller should be more than 80%.

A laboratory study was conducted to assess the efficiency of using a combination of flocculating substances to remove organic constituents from poultry chiller water. Rice bran in combination with commercial flocculant AP-273 (polyelectrolyte) removed 60% and 72% of chemical oxygen demand (COD) from low and high COD samples, respectively. Addition of granular activated carbon to the flocculant mixture increased COD removal to about 75%, respectively, from the same samples. Turbidity (suspended particles) of the chiller water was reduced by more than 90% using flocculant AP-273 plus rice bran. Chlorine demands were also greatly reduced. Soluble inorganic mineral content was not reduced by the combined flocculating substances. the residues collected after flocculation could be used as a feed ingredient, or as an organic fertilizer. Flocculation of chiller water would be a beneficial pretreatment to further recycling processes or to microfiltration of chiller water for reuse.

Commercial scale ceramic microfilters were used in plant tests to determine flux rate and operating parameters for waters from a poultry scalder, a poultry chiller, and brine from a delicatessen products chiller, under commercial conditions. Filtration produced clear permeate from all waters. Microorganism counts were essentially reduced to zero in scalder and chiller water permeates, with BOD reduced by about 70% in scalder water permeate and about 60% in chiller water permeate. Flux rates were in the range of 224-204 L/m2h for scalder water at 54°C and 114-81 L/m2h for chiller water at ambient temperature. Test results were used to project nonlabor operating savings and/or costs resulting from the use of microfiltration to recondition and reuse bath overflow. For a processing rate of 140 birds/min and bath size of 37,850 L (10,000 gal), an annual savings of $21,000-$26,000 were estimated for scalder water filtration, while annual costs of $65,000-$84,000 were estimated for chiller water filtration. For a deli brine bath size of 1,170 L (300 gal), annual costs of about $700 were estimated. Retentate heating and electrical usage associated with centrifugal filter pumps were projected as predominant cost factors. Besides costs, other factors such as nonchemical control of microbial growth, water savings, and reduced discharge levels may also be important reasons for considering microfiltration.

SUMMARY This study presents artificial neural network (ANN) methods in building energy use predictions. Applications of the ANN methods in energy audits and energy savings predictions due to building retrofits are emphasized. A generalized ANN model that can be applied to any building type with minor modifications would be a very useful tool for building engineers. ANN methods offer faster learning time, simplicity in analysis and adaptability to seasonal climate variations and changes in the building’s energy use when compared to other statistical and simulation models. The model herein is presented for predicting chiller plant energy use in tropical climates with small seasonal and daily variations. It was successfully created based on both climatic and chiller data. The average absolute training error for the model was 9.7% while the testing error was 10.0%. This indicates that the model can successfully predict the particular chiller energy consumption in a tropical climate. Copyright # 2005 John Wiley & Sons, Ltd.

A mathematical simulation of refrigerated seawater spray cooling of shrimp onboard a vessel is described. The simulation describes compressor and chiller performance and heat transfer between shrimp and recirculating spray water. It also accounts for conduction through the hull and for pump energy. A series of temperature measurements onboard vessels verified the model which can be used to evaluate the sensitivity of cooling rates to changes in equipment or operating procedures.

Equivalent levels of chlorine and chlorine dioxide (generated on-site) were established on the basis of bactericidal action in bird chiller water. When introduced directly into the chiller water after processed birds had begun to enter the chiller, 5 ppm CIO2 and 34 ppm CI2 were equally bactericidal. When introduced into the chiller with the fresh-water input, 20 ppm CI2 and 3 ppm CIO2 were equally effective. The use of about 1/7 as much CIO2 as CI2 would be less corrosive to processing equipment and provide the poultry industry with an alternative bactericide to chlorine.

Bird chiller water was filtered in a vertical tank pressure leaf filter by use of two grades of Diatomaceous Earth (DE). With both grades of DE, significant reductions were obtained in suspended solids, dissolved matter, grease, COD, BOD and total Kjeldahl nitrogen so that effective bactericidal treatment was accomplished with 26-28 ppm chlorine gas. Total aerobic counts, fecal coliforms and salmonellae were essentially eliminated from filtered, chlorinated water. The pH of filtered chiller water was similar to the pH of the unfiltered water. Clarity and light transmission compared favorably with potable water. Filtered, chlorinated chiller water was neither esthetically nor microbiologically objectionable. It was concluded that filtered chiller water could safely be reused to flume broiler giblets.

Why do we use cooling towers? The answer is simple. Cooling towers allow us to efficiently reject heat to the atmosphere at a lower temperature than other available processes. The key words in that last sentence are “at a lower temperature”.

Water samples from four points in a commercial broiler processing plant were compared to evaluate the feasibility of recycling processing water to the giblet flume without bactericidal treatment. Five microbiological parameters were examined: total aerobic counts, total and fecal coliform levels, salmonellae incidence and levels. By all methods of evaluation microbiological quality of water was best from the gizzard splitter and worst from the giblet flume. Giblets leaving the flume were microbiologically equal to giblets leaving the chiller despite differences in water quality. Apparently untreated water from the giblet splitter or chiller could be recycled to the giblet flume without sacrifice of product quality.

The water usage and waste loads were determined for ten unit operations in a modern poultry processing plant in Alexandria, Egypt. Concentrations of 10 wastewater parameters and 9 heavy metals, identification of 12 bacteria and enumeration of both total aerobic and coliform bacteria in the wastewater from these unit operations were determined to evaluate the potential for water reuse. In the scalder, washer and chillers, bacterial counts in the water and on the carcasses were directly related and increased with the length of water usage. Based on the study, countercurrent water use through the chillers and washer was planned after applying renovation measures for grease and bacterial reductions. Compressor cooling water quality was satisfactory for reuse in the scalder.

The effects of ozone on the quality of poultry chiller water and broiler carcasses were evaluated in a pilot plant size water recirculating poultry chiller. The microbial counts of ozone treated carcasses stored at 4.4°C were consistently lower than carcasses chilled under nonozonated conditions. Greater than 99% of all microorganisms washed from the carcasses were destroyed by the residual ozone in addition to significant reductions of one third in the chemical oxygen demand (COD) and a significant increase in light transmission (500 nm) of the treated process water. No significant carcass skin color losses, lipid oxidation, or off flavors resulted from ozone contact.

In order to conserve water and energy the feasibility of fluming necks with treated bird chiller water instead of potable water was examined. No significant differences were found in shelf-life, total aerobic counts, levels of fecal coliforms, or salmonellae incidence between necks flumed with potable water and necks flumed with diatomaceous earth-filtered chiller water or filtered, chlorinated chiller water. It was concluded that the use of potable water is not essential in all phases of broiler processing and that necks could be flumed safely with either filtered chiller water or filtered, chlorinated chiller water.

Hot-boned beef (excised 90 min postmortem) was chilled either by mixing coarse ground beef with CO(2) snow or by immersing ground beef chub packs in a brine chiller (-2 degrees C). Hamburger patties were prepared from both hot and cold-boned chub packed, coarse ground beef after 0, 7, 14, and 21 days of storage (0 degrees C). Microbiological quality of the hot-boned ground beef was either superior or equal to that of the control. Purge present in all the chub packs after 21 days of storage was 1.0%. Patties prepared from CO(2) chilled ground beef were more tender than control patties. Patties prepared from brine-chilled ground beef had greater cooking losses than patties prepared from cold-boned ground beef.

For tests of the feasibility of recycling water from the bird chiller, water samples from eight points in a commercial processing plant were evaluated by the following criteria: fecal coliform levels, total aerobic counts, salmonellae incidence and levels, BOD and COD. Probably due to a great dilution factor, water from the gizzard splitter was of better microbiological quality for recycling than water from the bird chiller but was higher in level of organic contaminants. If bactericidal treatment is omitted, water from the gizzard splitter would be preferable for recycling to giblet flumes. If bactericidal treatment is used, water from the bird chiller would be preferable because of its lower level of organic contaminants.

The post-cooling of high-ratio and all-purpose shortenings in a specially designed chiller, coupled with agitation during that cooling, has made it commercially practical to ship these bulk shortenings to the consumer within 24 hours after they have been packed.