The Influence from the Return Water Temperature of Condenser on the Unit and System COP of the Cold-Water Screw Unit Used on Cold Storage

2014 ◽  
Vol 953-954 ◽  
pp. 1449-1453
Author(s):  
Zhao Lei Ding ◽  
Chang Feng Zhang ◽  
Yun Fei Xu
Keyword(s):  
Energy Conservation ◽  
Mathematical Models ◽  
Water Temperature ◽  
Cold Storage ◽  
Cold Water ◽  
Variable Frequency ◽  
Refrigeration System ◽  
Evaporation Temperature ◽  
Return Water ◽  
Partial Load

The mathematical models of the storage refrigeration system of cold-water screw unit has been established.The operating condition of the unit and the system which working at partial load has been simulated,with different return water temperature of condenser.The influence from the return water temperature of condenser on the COP of the unit and system on the condition of different capacity of compressor has been analyzed, when the evaporation temperature is -10°C.The fact that it’s better to use start and stop operation with upload and download step by step rather than operate on the condition of low capacity of compressor, and that it’s beneficial for systemic energy conservation to use the variable frequency pump have been concluded.

The Influence from the Return Water Temperature of Condenser on the Cooling Capacity and Power Consumption of the Cold-Water Screw Unit Used on Cold Storage

2014 ◽  
Vol 941-944 ◽  
pp. 2461-2464
Author(s):  
Zhao Lei Ding ◽  
Feng Tong Li ◽  
Chang Feng Zhang
Keyword(s):  
Power Consumption ◽  
Water Temperature ◽  
Cold Storage ◽  
Cold Water ◽  
Cooling Capacity ◽  
Operational Cost ◽  
Evaporation Temperature ◽  
Storage Technology ◽  
Return Water ◽  
Partial Load

The mathematical models of the cold-water screw unit used on cold storage has been established.The operating condition of the unit which working at partial load has been simulated,with different return water temperature of condenser.The influence from the return water temperature of condenser on the cooling capacity and power consumption on the condition of different capacity of compressor has been analyzed, when the evaporation temperature is-10°C.The fact that the operational cost can be significantly reduced if the night cool storage technology is adopted.

scholarly journals Lagged recovery of fish spatial distributions following a cold-water perturbation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. D. Robertson ◽  
J. Gao ◽  
P. M. Regular ◽  
M. J. Morgan ◽  
F. Zhang
Keyword(s):  
Water Temperature ◽  
Species Distribution ◽  
Environmental Conditions ◽  
Cold Water ◽  
Heat Waves ◽  
Rapid Change ◽  
Nonlinear Effects ◽  
Spatial Distributions ◽  
Spatiotemporal Model ◽  
Yellowtail Flounder

AbstractAnomalous local temperature and extreme events (e.g. heat-waves) can cause rapid change and gradual recovery of local environmental conditions. However, few studies have tested whether species distribution can recover following returning environmental conditions. Here, we tested for change and recovery of the spatial distributions of two flatfish populations, American plaice (Hippoglossoides platessoides) and yellowtail flounder (Limanda ferruginea), in response to consecutive decreasing and increasing water temperature on the Grand Bank off Newfoundland, Canada from 1985 to 2018. Using a Vector Autoregressive Spatiotemporal model, we found the distributions of both species shifted southwards following a period when anomalous cold water covered the northern sections of the Grand Bank. After accounting for density-dependent effects, we observed that yellowtail flounder re-distributed northwards when water temperature returned and exceeded levels recorded before the cold period, while the spatial distribution of American plaice has not recovered. Our study demonstrates nonlinear effects of an environmental factor on species distribution, implying the possibility of irreversible (or hard-to-reverse) changes of species distribution following a rapid change and gradual recovery of environmental conditions.

scholarly journals Influence of Various Factors on Caffeine Content in Coffee Brews

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1208
Author(s):  
Ewa Olechno ◽  
Anna Puścion-Jakubik ◽  
Małgorzata Elżbieta Zujko ◽  
Katarzyna Socha
Keyword(s):  
Literature Review ◽  
Water Temperature ◽  
Geographical Origin ◽  
Cold Water ◽  
Water Type ◽  
Robusta Coffee ◽  
Caffeine Content ◽  
Type Water ◽  
Brewing Time ◽  
Coffee Brews

Coffee brews are one of the most popular drinks. They are consumed for caffeine and its stimulant properties. The study aimed to summarize data on the influence of various factors on caffeine content in brews prepared with different methods. The study was carried out using a literature review from 2010–2020. PubMed and Google Scholar databases were searched. Data on caffeine content was collected by analyzing the following factors: the influence of species, brewing time, water temperature, pressure, degree of roast, grinding degree, water type, water/coffee ratio as well as other factors (such as geographical origin). To sum up, converting caffeine content to 1 L of the brew, the highest content is that of brews prepared in an espresso machine (portafilter), with the amount of 7.5 g of a coffee blend (95% Robusta + 5% Arabica), and water (the volume of coffee brew was 25 mL) at a temperature of 92 °C and a pressure of 7 bar, but the highest content in one portion was detected in a brew of 50 g of Robusta coffee poured with 500 mL of cold water (25 °C) and boiled.

scholarly journals Combined Effects of Summer Water Temperature and Current Velocity on the Distribution of a Cold-Water-Adapted Sculpin (Cottus nozawae)

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 975
Author(s):  
Kaiji Suzuki ◽  
Nobuo Ishiyama ◽  
Itsuro Koizumi ◽  
Futoshi Nakamura
Keyword(s):  
Water Temperature ◽  
Climate Warming ◽  
Current Velocity ◽  
Cold Water ◽  
Environmental Gradients ◽  
Combined Effect ◽  
Influential Factor ◽  
Combined Effects ◽  
River Catchment ◽  
Water Abstraction

Clarifying the combined effects of water temperature and other environmental factors on the species distributions of cold-water fishes is the first step toward obtaining a better understanding of the complex impacts of climate warming on these species. In the present study, we examined the abundance and occurrence of the fluvial sculpin, Cottus nozawae, in response to water temperature along environmental gradients in northern Japan. The abundance survey was conducted in the Sorachi River catchment with two-pass electrofishing with a backpack electrofisher. For the occurrence survey, we carried out one-pass electrofishing in the Sorachi, Chitose, and Tokachi River catchments. Fish sampling was conducted once from July to August 2018 in the Sorachi River catchment, from May to June 2011 in the Chitose River catchment, and from July to September 2012 in the Tokachi River catchment. Generalized linear mixed models (GLMMs) and generalized linear models (GLMs) were used for the abundance and occurrence analyses, respectively. We found that the mean summer water temperature was the most influential factor on the distribution of C. nozawae; the abundance and occurrence were both negatively affected by increased water temperatures. In the occurrence model, occurrence probabilities of 0.9 and 0.5 for C. nozawae corresponded to mean summer temperatures of 12.0 and 16.1 °C, respectively. Furthermore, we identified a combined effect of water temperature and current velocity on the abundance of C. nozawae. The increased mean summer water temperature had a stronger negative effect on C. nozawae abundance under gentle flow conditions. While the precise mechanisms of this combined effect could not be determined in this study, stressors associated with low current velocities may increase their vulnerability to higher water temperatures. Our findings indicate that flow disturbances caused by human activities such as excessive water abstraction may exacerbate the negative impacts of climate warming on populations of C. nozawae in the future.

scholarly journals Fluctuating temperature of the mains water throughout the year and its influence on the consumption of energy for the purposes of DHW preparation

2018 ◽  
Vol 44 ◽  
pp. 00017 ◽  
Author(s):  
Agnieszka Chmielewska
Keyword(s):  
Water Treatment ◽  
Water Temperature ◽  
Cold Water ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Monthly Basis ◽  
New Model ◽  
Water Influence ◽  
Family Building ◽  
Cold Water Temperature

The article discusses the influence of the cold water temperature on the amount of energy consumed for the purposes of the DHW preparation in multi-family buildings. The article begins with a presentation of the DHW consumption readings from a multi-family building, recorded on a monthly basis during the period of 4 years. The readings constituted the base for calculating the demand for energy for the purposes of the DHW preparation. Subsequently, basing on the output water temperature readings from the water treatment plant, it was proved that the temperature of the mains water fluctuates throughout the year. The review of the available literature, as well as the measurements, confirmed that it is necessary to develop a new model of the cold water temperature that would take into account the type of intake in a water treatment plant. The final part of the article presents how the accepted assumptions about the temperature of the mains water influence the consumption of energy for the purposes of the DHW preparation.

Skinfolds and resting heat loss in cold air and water: temperature equivalence

1975 ◽  
Vol 39 (1) ◽  
pp. 93-102 ◽  
Author(s):  
R. M. Smith ◽  
J. M. Hanna
Keyword(s):  
Heat Transfer ◽  
Water Temperature ◽  
Heat Loss ◽  
Air Temperature ◽  
Indirect Calorimetry ◽  
Cold Water ◽  
Heat Conductance ◽  
Air Temperatures ◽  
Body Core ◽  
Male Subjects

Fourteen male subjects with unweighted mean skinfolds (MSF) of 10.23 mm underwent several 3-h exposures to cold water and air of similar velocities in order to compare by indirect calorimetry the rate of heat loss in water and air. Measurements of heat loss (excluding the head) at each air temperature (Ta = 25, 20, 10 degrees C) and water temperature (Tw = 29–33 degrees C) were used in a linear approximation of overall heat transfer from body core (Tre) to air or water. We found the lower critical air and water temperatures to fall as a negative linear function of MSF. The slope of these lines was not significantly different in air and water with a mean of minus 0.237 degrees C/mm MSF. Overall heat conductance was 3.34 times greater in water. However, this value was not fixed but varied as an inverse curvilinear function of MSF. Thus, equivalent water-air temperatures also varied as a function of MSF. Between limits of 100–250% of resting heat loss the followingrelationships between MSF and equivalent water-air temperatures were found (see article).

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