DESIGN, CONSTRUCTION AND TESTING OF A COLD STORE WITH WATER-COOLED CHILLER

Objective of this research was to design, construction and test of a cold store with chiller unit. Dimensions of the cold store were 5x4x3m. Heat load was calculated and capacity of cooling system was determined. Ambient temperature was set 2oC and relative humidity 90% for cold store testing. Ambient temperature, relative humidity and air velocity were measured for 3 different levels and 12 points for each level in the cold store. Total heat load and capacity of cooling system were calculated 5222 kcal/h. and 6.07 kW respectively. The descriptive statistics were calculated for the ambient temperature; mean, 2.82oC, standard deviation 0.02oC and CV(%) 0.56, and for the relative humidity; mean 88.01%, standard deviation 0.61 (%) and CV(%) 0.70 and for the air velocity mean 0.37m/s, standard deviation 0.22 m/s, CV 33.45 %. Even the air velocity CV was high, the ambient temperature and relative humidity variations were evaluated very good.

CFD MODELLING AND VALIDATION OF AMBIENT FACTORS IN EVAPORATIVE COLD STORE FOR PEACH STORAGE

Spatial variation of temperature and relative humidity were estimated with Computational Fluid Dynamics (CFD) at top, middle and base levels for peach storage at +1oC and 90% relative humidity and verified with measured data in a cold store with evaporative cooling system. Storage temperature was +1oC and relative humidity 90% for peach storage. Ansys Fluent Software was used for CFD modelling. CFD models were validated with sensors measurements. Results were evaluated by using descriptive statistics, relative error and variance analyses. Mean difference between the model and measurements was calculated as 0.51oC for ambient temperature and as 3.47 % for relative humidity. Relative error of the CFD model was calculated as 9.77 for the ambient temperature and 1.29 for relative humidity for peach storage. The developed CFD models estimated the ambient factors with an acceptable error in the evaporative cold store for peach storage.

Improvement of Properties of an Insulated Wall for Refrigerated Trailer-Numerical and Experimental Study

In the paper, we report our research on the improvement of thermal efficiency of refrigerated trailers by modification of their wall structure by placing a layer of phase change material inside them. The research was carried out in the field of transport, meeting the requirements of all classes provided for in the ATP agreement for refrigerated trailers. As part of the research, we formulated a numerical model of the proposed design of the refrigerator walls, which was subsequently validated by comparing the modeling results with the results of experimental tests carried out on a test bench designed specifically for this purpose. Based on the validated simulation conditions, we formulated the numerical model of a full-scale refrigerated semi-trailer, which was numerically tested under the conditions specified in the ATP Agreement. The results proved that adding a 6 mm layer of the SP-24 phase change material in each of the walls of the cold store allows the temperature inside the trailer to be kept below −20 °C for a period of 24 h without the need to supply cold from the outside during operation. The passive refrigerated semi-trailer system implemented in this manner with 6 mm PCM layer allows for a reduction in primary energy consumption by up to 86% in a period of 22 h. The mentioned percentage did not take into account the efficiency of the cooling system of the phase change material.

District Heating and Cooling Systems

Decarbonisation of the energy sector is a crucial ambition towards meeting net-zero targets and achieving climate change mitigation. Heating and cooling accounts for over a third of UK greenhouse emissions and, thus, decarbonisation of this sector has attracted significant attention from a range of stakeholders, including energy system operators, manufacturers, research institutions and policy makers. Particularly, the role of district heating and cooling (DHC) systems will be critical, as these two energy vectors are central to our lives not only for comfort and daily activities, but also to facilitate productive workplaces and to run a variety of industrial processes. The optimal operation of DHC systems and the design of efficient strategies to produce heat and cold, store thermal energy, and meet heating and cooling demands, together with an increased integration of low carbon technologies and local renewable energy sources, are vital to reduce energy consumption and carbon emissions alike. This chapter reviews relevant aspects of DHC systems, their main elements, automatic control systems and optimal management.

Aspects of adapting the cooling installation in a food cold storage system to the applicable f-gas regulations

The paper presents the methodology of the analysis of the cooling system reconstruction in a food cold store under the regulations applicable from the beginning of 2020. They result from the so-called the F-Gas Act concerns the use of refrigerants with a low environmental impact. First, the elements of the existing regulations on the use of refrigerants were discussed. This part of article focus mainly on the F-Gas Act and the regulations it entails. Then, the refrigerants used so far in refrigeration systems were compared with substitutes, which were the only ones that have been approved for use since 2020, thanks to the low GWP index. Their properties are briefly described, along with the benefits (primarily for the environment) of their use. The main part of the work is the analysis of the reconstruction of the cooling system to use an alternative refrigerant. During the work, the construction of the cold storage was analyzed together with the system currently working in analysed location. Then, the heat balance was calculated, thanks to which it was possible to determine the demand for cold. Than, several refrigerants that meet the latest standards and application regulations were selected. Their operating parameters were examined, the possible variants of use were compared in relation to the determined demand for cooling and the most important operational features were summarized.

Project Management Procedure for the Construction of Cooled Stores for Drugs and Medicine on Iraq

Iraq is one of the countries that fluctuates in the climate greatly, as well as is characterized by a very hot summer, so the cold storage sector is very important in this country, especially medicine and medical supplies stores. The warehouse sector is one of the most important construction sectors. It includes many facilities, the most important of which are cold stores. After researching and investigating the necessary data in managing this type of project, it was found that there is a great shortage in that data, and this deficiency may be one of the reasons for the failure of this sector in Iraq. In order to evaluate the information and available data related to the management of cold store projects, a questionnaire was asked to take the opinion of engineers and specialists in this field. The questionnaire included several axes, and each axis included a group of questions. The questions were divided depending on their relationship to each other. The questions included gender, age, specialization, experience and the fact that the engineer previously worked in project management and other questions. This article proposes waterfall framework as project management framework for the studied case projects.

Effect of Wrapping Materials and Storage Time on Shelf Life of Tuberose (Polianthes tuberosa L.)

Background: The use of wrapping material during storage of cut flowers creates a modified atmosphere which reduces flower metabolism during storage, thereby slowing carbohydrate consumption as respiratory substrate. The main problem related to dry storage is moisture loss or desiccation. Keeping in view the above aspects, the present study was conducted to enhance the shelf life of tuberose.Methods: The experiment was carried out at Post-Harvest Laboratory of Department of Horticulture, COA, CCS HAU, Hisar during the cropping season (March to September) of year 2019. It was laid out in CRD (factorial) with three replications and twenty-four treatment combinations, comprising of six wrapping materials (newspaper, butter paper, chart sheet, low density polyethylene of 100µ, high density polyethylene of 200µ and control as without wrapping) and four storage time (1, 4, 7 and 10 days), were tested. After harvesting, cut spikes were wrapped in wrapping materials and kept in cold-store at low temperature (less than 5°C), thereafter cut spikes were placed in vase solution (4% sucrose plus 300 ppm 8-HQC) for recording observations on floral parameters. Result: Among different wrapping materials, the butter paper wrapped cut spikes observed better in most of the parameters followed by LDPE (100µ) wrapped cut spikes. Among the storage time, storage of cut spikes for 1 day observed better in most of the parameters except time taken up to opening of first pair of florets and total post-harvest life. Overall, butter paper wrapped cut spikes stored for 1 day performed better in term of floret diameter (46.73 mm), floret length (56.10 mm), floret longevity (2.89 days), appearance (3.70/5.0 scale), florets opened at a time (32.30%), total opened florets (54.32%), marketable vase life (6.53 days), total vase life (11.17 days), weight loss (17.08%) and solution consumed (135.33 ml) by the spikes. However, the cut spikes wrapped in butter paper stored for 10 days were found better with early opening of first pair of florets (0.95 days) and maximum post-harvest life (20.10 days).