Refrigerant Loss Research Articles

The silent competition between humans and livestock for maize has brought about the recent researches on the use of unconventional feed ingredients,such as dried watermelon rinds (DWMR),as an inclusion in livestock feed. This study was therefore conducted to assess the effect of dietscontaining graded levels of DWMR on rabbits’meatquality.Eighty (80) crossbreed, unsexed weaner rabbits with the mean weight of 630g were used for this study, allocated on weight equalization basis into four (4) treatment groups (0%, 5%, 10% and 15% of DWMR inclusion levels, representing T1, T2, T3 and T4 respectively and further divided into five (5) replicates of 4 rabbits. A total of 24 rabbits, 6from each treatmentwere slaughtered formeat quality assessment.Results revealed a significant (P<0.05) influenceof DWMRin the fat and crude fibre(within the negligible range of 1-2%)contents of the meat.Fat was highest (14.21%) in T3while fibre was highest (1.11%) in T4. Cooking loss, refrigeration loss,water absorptive powerandcolourof meat from rabbitswere not significantly (P>0.05) affected by DWMR.Although lipid profile was not significantly (P>0.05) affected by DWMR, significant (P<0.05) differences were observed in the levelsof Malondialdehyde (MDA), Gluthatione (GSH) and Catalase (CAT).MDA level was least at the 5% DWMR treatment group while the 0% and 10% DWMR treatment groups had the highest level of GSH and CAT respectively.Meat from rabbits fed 15% DWMR recorded the highest score for tendernessin sensorial profile.It wasthenconcluded thatup to 15 %ofDWMRin rabbits’ diets had no negative effecton the quality of their meat.

The known methods to assess the efficiency of heat transformers do not consider pressure losses in the transformer circuit. These losses seem to be insignificant. However, the issue is how insignificant they are and whether they should still be considered. The purpose of the study is to modernize available methods to calculate heat transformers to take into account the impact of refrigerant pressure losses in the heat transformer circuit. The methods of assessing the efficiency of a vapor compression and absorption transformers are based on the methods of V. Maake and P.A. Trubaev, and the methods of T.V. Morozyuk and L.S. Timofeevsky, respectively. The method of A.N. Noskov has been used to clarify the efficiency of the compressor. The hydraulic resistances of heat exchangers and pipelines in the circuits of heat transformers have been determined using available methods of domestic authors. The obtained resistance values have been displayed on the P-h diagram of the cycle. A modernized method for assessing the efficiency of vapor compression and absorption heat transformers has been obtained, considering pressure losses in the circuit. Calculations of the efficiency indicators of heat transformers are carried out using the obtained methodology. The results of the calculations correspond to the experimental data obtained earlier by V.O. Mamchenko and A.A. Malyshev. Pressure losses in the circuit of the vapor compression heat transformer reduce the transformation ratio for example under study by 5,4 %, and in the circuit of the absorption heat transformer by 0,4 %. Accordingly, when assessing the efficiency of vapor compression heat transformers, pressure losses play a significant role.

An experimental investigation on frosting characteristics and performance of microchannel evaporators with varied aspect ratios

This study investigated the effects of curcumin nanoparticles on the flesh quality of largemouth bass on a high-carbohydrate diet. A total of 180 fish (11.01 ± 0.02 g) were fed three semi-purified diets: the Control group (LC) were supplemented with standard carbohydrate (10%), the experimental group (HC) were supplemented with 15% carbohydrate, and the experimental group were supplemented with 0.2% nano-curcumin added to 15% carbohydrate (HCN) for 6 weeks. Results showed that a* value, taurine, valine, isoleucine, histidine, cystine, fatty acids (C17:0 and C20:2n6), MDA (malondialdehyde) content, and SOD (Superoxide dismutase) activity were significantly elevated (p < 0.05) in HC. Muscle fibers showed significant increases in horizontal diameter, longitudinal diameter, and cross-sectional area (p < 0.05), as well as up-regulated expression levels of the MRFS (myogenic regulatory factor) family gene and MSTN (myostatin) (p < 0.05), and a significant decrease in C16:1n7 in HC (p < 0.05). Importantly, the HCN group enhanced the muscle quality of largemouth bass by elevating the L* value, valine, isoleucine, arginine and cystine, C20:2n6, decreasing (p < 0.05) refrigeration loss, chewability, firmness and hardness, then MDA content and SOD activity, and downregulating (p < 0.05) MSTN and MRFS family gene expression levels to improve largemouth bass muscle quality.

Refrigerants are a critical component of air conditioning and heat pump systems, but their high global warming potential has led to increasing concerns about their environmental impact. This research quantifies leakage from Schrader valves commonly used in air conditioning equipment. These valves serve as access points for refrigerant circuits and are often cited by service technicians as a source of leaks, contributing to greenhouse gas emissions. The study conducted laboratory testing of Schrader valves using an innovative experimental apparatus that tracked pressure and temperature of nitrogen gas contained by the valve over a 64-h test. The study found that 8 out of 61 used Schrader valves tested leaked at rates that would result in substantial refrigerant loss (M = 1,280 g/yr, SD = 3,168 g/yr, range = 9.4 to 9,117 g/yr). Gasketed caps were found to prevent refrigerant loss. Combining a Schrader valve with a gasketed cap significantly reduces the risk of leaks, and their use should be encouraged in air conditioning systems. The methodology developed for estimating leak rates from Schrader valves could be applied to other components in refrigeration systems, contributing to more comprehensive efforts to reduce refrigerant emissions.

PurposeThis paper investigates the impact of CO2 vs CO2 “equivalents” (CO2e) by analyzing fugitive emissions, with a particular focus on Fluorinated gases (F-gases), arising from refrigerant leakages in buildings. F-gases are an especially powerful set of GHGs with a global warming potential hundreds to thousands of times greater than that of CO2.Design/methodology/approachThe significant impact of CO2e is tested by means of an empirical study with current consumption data from German food retail warehouses. This evaluation involves the analysis of the Carbon Risk Real Estate Monitor's country- and property-type specific pathway, coupled with a paired samples t-test to examine the hypotheses. The assessment is undertaken by evaluating the type of gas and the amount of leakage reported in the baseline year, subsequently converting these values to CO2e units.FindingsOn average, F-gases account for 40% of total building emissions and nearly 45% of cumulative emissions until 2050. In light of ongoing climate change and the rising number of Cooling Degree Days (CDDs), it becomes imperative to assess both the environmental and economic impact of F-gases and to transition toward environmentally friendly refrigerants.Originality/valueThe analysis sheds light on the seldom-addressed threats posed by CO2e emissions stemming from refrigerant losses. By identifying these threats, investors can devise strategies to mitigate potential future costs and carbon risks.

Abstract A mathematical model for an air conditioning system used in five‐seater cars is developed with R1234ze(E) and R134a refrigerants, consisting of real system geometry like an evaporator, compressor, condenser, and thermostatic expansion valve. The mathematical model includes refrigerant properties, heat transfer, and pressure loss correlations for two‐phase and single‐phase regions. The performance parameters of a system like evaporator cooling duty, condenser heat loss, compressor power, refrigerant flow rate, and compressor volumetric efficiency obtained from a mathematical model are validated with the results of an experimental facility developed with R134a. The uncertainty analysis performed for the testing facility showed below 11% deviation. The simulation and experimental results showed an overall 10%–15% difference. It is found that the experimental cooling capacity with R134a and numerical cooling capacity with R134a show a 4%–12% variation, experimental cooling capacity with R134a and numerical cooling capacity with R1234ze(E) show a 7%–20% variation, and numerical cooling capacity with R134a and numerical cooling capacity with R1234ze(E) show a 5%–15% variation for the given range of compressor speed (500–1500 rpm), and condensing temperature (26–45°C). The study concluded that R1234ze(E) could potentially replace R134a because it has similar thermophysical properties and an average performance difference of up to 10% with R134a. Due to the limitations of the electric motor used to drive the compressor, tests in the current study were conducted at modest compressor speeds (500–1500 rpm). Future research will focus on experiments with high compressor speed (in the range of 1500–4000 rpm) and R1234yf and R1234ze(E) refrigerants for performance evaluation of automobile air conditioning systems.

Comparative study on four autocascade refrigeration cycles based on energy, exergy, economic and environmental (4E) analyses

Black pepper (Piper nigrum) is a plant highly valued for its functional aromatic compounds. To increase bioavailability of its phytochemicals, a novel approach to extraction using microwave heating and optimization was investigated. Fixed (microwave power and particle size) and variable (heating time and solvent volume) extraction criteria were applied to obtain aqueous extracts, followed by the optimization of the quality of extracts by subjecting the extracts to meat quality test using the central composite design. Thereafter, quality indices (pH, 2-thiobarbituric acid reactive substance value, refrigeration loss, colour and cooking loss) of meat subjected to storage were determined and the outcomes were analysed using response surface methodology. A total of six optimised solutions were derived but the best extraction criteria (variable) were 87.28 min and 364.26 mL of heating time and solvent volume respectively with a desirability value of 0.624, while microwave power and particle size were kept constant. Afterwards, selected optimised extraction criteria was applied, and black pepper aqueous extract obtained was compositionally analysed using Gas Chromatography Mass Spectrometry. Remarkably, a total of 71 compounds were extracted, comprising element-based compounds such as silicon, nitrogen, sulphur and iodine. Two silicon and nitrogen-based compounds as well as one sulphur and nitrogen-sulphur based compound were obtained while seven iodine-based compounds were discovered alongside other functional compounds. This approach results in green and efficient extraction process with increased bioavailability of functional compounds. However, further modifications of extraction criteria can be applied to upscale the desirability level (score) for increased extraction efficiency.

The trial was conducted to investigate the effects of limonene, allicin and betaine supplementation in low fish meal (FM) diet on growth performance, antioxidant capacity, meat quality and intestinal health in largemouth bass (M. salmoides). The biting-balls test and feeding trial were successively conducted. For the one, the results of the biting-ball test showed that with the increase of the concentration of the three attractants, the attracting effect firstly increased, then decreased, and the effect reached maximum at 0.2% concentration. (P < 0.05). Further, a 9-week feeding trial was conducted using five diets, including a basal diet with 30% and 40% fish meal without attractant, 30% fish meal supplemented with 0.2% limonene, 0.2% allicin or 0.2% betaine (the diets were named FM30, FM40, FM30 + L, FM30 + A, FM30 + B, respectively). The results demonstrated that adding limonene, allicin and betaine at concentration of 0.2% to the low fish meal feed could improve final body weight, weight gain rate, and specific growth rate of M. salmoides but only in 4 weeks (P > 0.05). Besides, dietary supplementation with attractants could significantly reduce the content of MDA in serum and liver, and increase the activity of GSH in liver (P < 0.05). Compared with FM30 group, the supplementation with limonene, allicin or betaine diet had higher pH, redness (a*), yellowness (b*) (P > 0.05), and lower refrigeration loss, cooking loss values (P < 0.05). Furthermore, supplementation with attractants groups had higher values for villus height, lamina propria, crypt depth, submucous layer, and serous layer (P < 0.05). Taken together, these results indicated that limonene, allicin and betaine had a time effect on the growth performance, and could improve antioxidant capacity, meat quality and intestinal health of M. salmoide.

Numerical Study on the Effect of Nozzle Incident Angle on the Overall Performance of Gas Wave Refrigerator

Abstract Young rabbits does fed ad libitum diets often show parturition problems such as dystocia and abnormal presentation, resulting in reduced numbers of kits. This can be linked to excessive fatness of the does. Several studies have documented the effect of feed restriction on rabbits, but only limited information exist on the carryover effect of maternal feed restriction exerts on meat quality attributes of the offspring produced from such restriction. This study evaluated the influence of maternal feed restriction and vitamin E inclusion during pregnancy on meat quality of rabbit kits. Seventy-five rabbits, consisting of sixty 20-week-old does and 15 mature bucks, were used in the experiment. Treatments consisted of two levels of feed restriction (0 and 15 %) applied at three different periods during pregnancy (15 – 19, 20 – 24, or 25 – 29 days) with or without vitamin E dietary inclusions (0 and 300 mg/kg). The pregnant does were divided into twelve treatment groups, each containing five replicates of one rabbit each. The experiment was in a 2 × 3 × 2 factorial layout in a completely randomised design. After kindling (between days 28 – 31 of pregnancy) the resulting kits (a total of 180 kits) were arranged on treatment basis of their mothers and managed for a period of 56 days; that is 15 kits per treatment, each replicated 5 times (each replicate contained 3 kits). After 56 days of experiment, the data were collected on meat pH, total cholesterol, crude fat, crude protein, thermal shortening and refrigeration loss. Feed restriction during pregnancy with or without dietary vitamin E (no addition and 300 mg/kg) resulted in a significant (p < 0.05) influence on meat quality attributes of growing rabbits as total cholesterol (555.00 ± 6.06) decreased in the meat of rabbits whose mothers were feed-restricted during pregnancy. On the other hand, maternal feed rationing with or without vitamin E did not significantly (p > 0.05) affect the crude protein and thermal shortening of their slaughtered offspring. In conclusion, maternal feed rationing during pregnancy can be adopted as a feeding strategy in manipulating meat quality indicators of growing rabbits as total cholesterol concentrations decreased which is a good indicator that the meat is safer and better for consumers in order to prevent health-related challenges.

This study evaluated the effect of apple cider vinegar (ACV) on the carcass characteristics and meat quality of broiler chickens. A total of 300 broilers (Arbor Acre) were randomized to six treatments replicated 5 times (50 birds/treatment and 10 birds/replicate) from 2days old till the sixth week of age in a 2 by 3 factorial layout consisting of dosages (5.0mL/L and 10.0mL/L ACV) and administration frequency (antibiotics following standard schedule, twice/week ACV and thrice/week ACV). At the sixth week, sixty birds (10 birds/treatment) were selected for carcass yield, cut part yield, organ weight, meat technological properties, lipid profiles, and malondialdehyde (MDA) level evaluation. Data obtained were subjected to two-way ANOVA followed by Tukey's test at a P < 0.05 significant level. Birds administered 5.0mL/L ACV thrice weekly presented a significantly (P < 0.05) higher plucked, eviscerated, dressed, thigh and breast weight compared with the other treatments. The spleen of birds in the control group was significantly (P < 0.05) heavier than those administered ACV. The meat from the 5.0mL/L ACV group had significantly higher (P < 0.05) water absorptive power and lower refrigeration loss, as depicted in the main effect table. Meat cholesterol, phospholipids, and MDA levels did not differ across the treatments except triglyceride, which was significantly (P < 0.05) lower in the 5.0mL/L ACV thrice-weekly group. This study concludes that ACV administration could improve carcass yield and meat quality indices. Thus, its use as an alternative to conventional antibiotics for broiler chickens might be beneficial.

Application and analysis of multi-stage flash vaporization process in steam production in high-temperature heat pump system with large temperature difference

Scombroid fish poisoning (SFP) is an acute illness caused by the consumption of poorly preserved fish containing high levels of histamine. Symptoms develop within 1-2 h, with gastrointestinal, dermatologic, and cardiopulmonary manifestations. The diagnosis relies exclusively on the clinical picture. To describe an onsite clinical-epidemiological study of a massive outbreak of SFP occurring in Chile. Descriptive study of an outbreak occurring in a closed Convention Center after lunch with Chilean Palometa or Seriola lalandi (Yellowtail kingfish). An Onsite questionnaire was answered by all attendants within 24 h. Local health officials supervised the place with a second survey and sample recollection of suspected fish. Eighty-three adults attended the event, of which 81 ate fish. Mean age: 58.5 years old, 82.7% women. The symptomatic attack rate of people eating suspected poisoned fish was 79% (64 out of 81 participants). Most common symptoms included: diarrhea (68%); headache (64%); flushing (64%) and diffuse redness (56%). Mean incubation period: 77 min (30-240 min). 98.4% of patients recovered within 10 h. Ten patients were referred to the emergency room, but none were admitted. There was a presumption of loss of refrigeration in the handling of fish, and confirmation of SFP by clinical basis, incubation period and attack rate. Fish was the only food item associated with illness (Odds ratio: 19, p = 0.014; Fisher two tails). This is one of the 5 largest outbreaks of SFP with fresh fish, ever reported in the literature. The clinical picture and rapid onset of symptoms made it possible to suspect SFP allowing timely management of patients. It is relevant to spread the knowledge about this underdiagnosed and underreported syndrome.

&#x0D; &#x0D; &#x0D; &#x0D; A study was undertaken to determine effect of nutritional value of melon (Colocynthis citrillus) husk (MH) and palm (Elaeis guineensis) oil slurry (POS) on quality of chevon obtained from West African Dwarf (WAD) goats finished on four diets viz. diet 1 (0% MH, 0% POS); diet 2 (50% MH, 0% POS); diet 3 (0% MH, 50% POS) and diet 4 (50% MH, 50% POS). All animals were fed a basal diet of Panicum maximum ad libitum. After sixty days, eight goats (two goats per treatment) were slaughtered and muscles obtained from their forelegs. A sample of the raw meats was taken for pH measurement and Fatty acid analyses while the remaining was cooked by boiling and used for proximate analysis, cooking and refrigerated losses, and sensory evaluation. Data were subjected to one – way analysis of variance in a completely randomized design. Percent dry matter of the experimental diets ranged from 89.53% to 89.81%. The cooking weight loss for chevon showed no significant (P&gt;0.05) difference but refrigerated weight loss (drip loss) showed significant (P&lt;0.05)difference due to diets; lowest values were recorded on diets 2 (0.96g) and 4 (0.91g), respectively. Chevon obtained from animals fed diet 3 had the lowest percent crude protein content (21.51%) and highest cooking and refrigeration losses of 4.44% and 23.51%, respectively. Chevon obtained from all the diets fed gave significant (P&lt;0.05) lower percentage values for linolenic acid compare with the control, while chevon from goats fed diet 3 gave a reduced percentage value of saturated fatty acids. In all the parameters considered for sensory evaluation, only flavour and saltiness showed significant (P&lt;0.05) difference. It was concluded that Melon husk and palm oil slurry can be added at the various inclusion rates in this study depending on consumer preferences for either nutrient qualities or sensory properties of meat.&#x0D; &#x0D; &#x0D; &#x0D;

A total of one hundred and forty four grower (56-84d) turkeys were used to investigate the effect of dietary supplemental L-arginine on growth response, physico-chemical and sensory properties of the resultant breast meat. Dietary treatments consisted of basal diet supplemented with 0 (control), 0.05 and 0.10% L-arginine, respectively. A completely randomized design was used with turkeys randomly allotted to 18 pens; each pen housed eight birds. Six pens were assigned to each treatment. Growth performance of the birds, cook loss, refrigeration loss, freeze loss and water absorptive power of the breast meat were measured. Finisher turkeys fed diet supplemented with 0.05 % L-arginine and control group had reduced (P &lt; 0.05) feed intake and improved (P &lt; 0.05) feed conversion ratio. Meat samples from turkeys fed diet supplemented with L-arginine showed increased (P&lt;0.05) cook loss weight (in g) and percentage cook loss when compared with control group. Turkeys fed diet supplemented with 0.10% arginine had the highest (P&lt;0.01) percentage refrigeration loss, freeze loss weight (g) and percentage freeze loss. Increasing supplementation level of arginine showed a linear reduction (P&lt;0.001) in the thaw weight of breast meat. Sensory parameters of meat sample were not influenced (P&gt;0.05) by varying level of arginine supplemented. In conclusion, arginine supplementation seems to weaken the muscular cross-bridges in breast meat and hence resulted in higher cook loss, refrigerated loss and freeze loss.

There is consumer's preference for tender meat. The use of tenderizers to soften meat helps to reduce nutrient losses due to prolonged cooking. This study was conducted to compare the effects of four unconventional marinades (Pawpaw leaves extract, Lime-juice, and Carbonated drinks and distilled water) on the quality of beef. One thousand five hundred grams (1500 g) of beef excised from the thigh muscle was cut into twelve whole pieces of similar sizes and were randomly distributed into four experimental groups in a Complete Randomized Design (CRD). Treatment groups were randomly allotted to experimental marinades measuring 300mL with each marinade containing 100mL of tenderizers. Marination spanned for a period of 24 hours at a temperature of 4 °C. Data collected were: beef proximate composition, weights with pH of beef and marinades, cook and refrigeration losses and sensory scores. Results showed significantly (P&lt;0.05) higher fat and Fe content in beef treated with Lime-juice and Pawpaw leaves extract-based marinades respectively. Marination did not affect (P&gt;0.05) crude protein, ash, moisture content, and calcium. Weights and pH from beef and marinades varied significantly (P&lt;0.05) after marination. Pawpaw leaves extract-based marinades produced more (P&lt;0.05) tender beef; while beef marinated with carbonated drink marinade had significantly (P&lt;0.05) better flavour and overall acceptability. It is therefore concluded that carbonated drink based marinades produced beef with the best quality.

Tonic root has been speculated to improve Libido and this could have effect on performance and carcass traits of the animal. Afifty-six days experiment was conducted to determine meat quality of Abor acre Strain of broiler chickens fed graded dietary inclusion of supplemental white ginger (Mondia whitei). One hundred and eighty, one day-old broiler chicks were assigned to five treatment groups with three replicates per group. Birds on treatment one were fed concentrate with no supplements, those on treatment two had concentrate + 0.5g Mondia whitei per kg feed, treatment three had concentrate + 1g Mondia whitei per kg feed; Treatment 4 had concentrate with 1.5g Mondia whitei per kg feed and treatment five had concentrate + 2g Mondia whitei per kg feed. At the end of the eight weeks feeding trial, three birds each from each replicate of five treatment groups were randomly selected, deprived of food for 12 hours prior to slaughtering. After the traditional slaughtering method, feather plucking and evisceration were done and breast muscles were excised from the carcasses for quality parameters evaluation. The results showed significance (P&lt; 0.05) in some measured parameters such as colour, yellowness (b*) and Lightness (L*). Highest (P&lt;0.05) triglyceride content of meat (145.33 mg/dL) was recorded in the meat of birds fed inclusion level at 0.5g/kg and the lowest value (91.67mg/dL) in the meat of birds fed inclusion level of 1g/kg. Breast muscles had the highest (P&lt;0.05) pH score 6.72 at 1g/kg inclusion level and least value of 6.51 was in the control group. Dietary inclusion of Mondia whitei showed no significant (P&gt;0.05) effect on cholesterol, high density lipoprotein (HDL) and low-density lipoprotein (LDL). Although superoxide dismutase (SOD) and water absorptive power were not significantly (P&gt;0.05) influenced, cooking and refrigeration loss as well as thiobarbituric acid reactive substance (TBARS) in meat were significantly (P&lt;0.05) lowest in birds fed 1g/kg dietary inclusion level of Mondia whitei. Some phytochemicals and overall sensory acceptability were statistically influenced by the dietary treatments.

This experiment was designed to determine the meat quality and lipid profile of broiler chickens fed diets containing turmeric (Curcuma longa) powder (Tur) and cayenne pepper (Capsicum frutescens) powder (Cay) as antioxidants. Two hundred and forty three (two-week old) Abor Acre broiler chicks were randomly allotted to nine treatment groups of 27 birds each, consisting of three replicates of nine birds each in a completely randomised design. Three levels of Tur (0, 2 and 4 g/kg) and three levels of Cay (0, 1 and 2 g/kg) were used to provide nine dietary treatments. Meat quality indices such as cook and refrigerated losses, water absorptive power, etc were measured and determined at the 8th week. Broiler Chickens fed the basal diet had highest meat dry matter, protein content and least (p&lt;0.05) meat pH, cook and refrigeration loss values. Meat triglyceride and meat malondialdehyde value was best (p&lt;0.05) in treatments fed dietary 2 g/kg Cay, while chickens fed 2 g/kg Cay, 2 g/kg Tur + 1 g/kg Cay and 2 g/kg Tur + 2 g/kg Cay had better meat lipoprotein values. For meat sensory characteristic, meat flavour of broiler chickens fed diets containing 2 and 4 g/kg dietary Tur, were moderately liked while overall flavour was best (p&lt;0.05) in groups fed the basal diet with no dietary additive. It was evident in the study that the dietary inclusions of the test ingredients limited lipid oxidation, thus improved storage duration and meat flavor.&#x0D; &#x0D;