Water Supply Rates for Recirculating Evaporative Cooling Systems

2018 ◽  
Vol 34 (3) ◽  
pp. 581-590 ◽  
Author(s):  
Joseph L. Purswell ◽  
John E. Linhoss ◽  
Carson M. Edge ◽  
Jeremiah D. Davis ◽  
Jesse C. Campbell

Abstract. Evaporative cooling (EC) is an important tool to reduce heat stress in animal housing systems. Expansion of ventilation capacity in tunnel ventilated poultry facilities has resulted in increased water demand for EC systems. As water resources become more limited and costly, proper planning and design of water supply systems is critical to ensure demand is met during periods of heat stress which increase EC use and bird water consumption. Few estimates of EC water use in animal housing applications are available in the literature and available estimates are geographically limited or rely on extreme weather events. The goal of this analysis was to provide guidance for EC water supply design to accommodate estimates of peak demand, rather than average consumption rates. Keywords: Ventilation, Broiler house, Water conservation, Housing design.

2017 ◽  
Vol 18 (1) ◽  
pp. 214-221
Author(s):  
K. L. Lam ◽  
P. A. Lant ◽  
S. J. Kenway

Abstract During the Millennium Drought in Australia, a wide range of supply-side and demand-side water management strategies were adopted in major southeast Australian cities. This study undertakes a time-series quantification (2001–2014) and comparative analysis of the energy use of the urban water supply systems and sewage systems in Melbourne and Sydney before, during and after the drought, and evaluates the energy implications of the drought and the implemented strategies. In addition, the energy implications of residential water use in Melbourne are estimated. The research highlights that large-scale adoption of water conservation strategies can have different impacts on energy use in different parts of the urban water cycle. In Melbourne, the per capita water-related energy use reduction in households related to showering and clothes-washing alone (46% reduction, 580 kWhth/p/yr) was far more substantial than that in the water supply system (32% reduction, 18 kWhth/p/yr). This historical case also demonstrates the importance of balancing supply- and demand-side strategies in managing long-term water security and related energy use. The significant energy saving in water supply systems and households from water conservation can offset the additional energy use from operating energy-intensive supply options such as inter-basin water transfers and seawater desalination during dry years.


2020 ◽  
Author(s):  
Jolijn van Engelenburg ◽  
Erik van Slobbe ◽  
Adriaan J. Teuling ◽  
Remko Uijlenhoet ◽  
Petra Hellegers

Abstract. Developments such as climate change and growing demand for drinking water threaten the sustainability of drinking water supply worldwide. To deal with this threat, adaptation of drinking water supply systems is imperative, not only on a global and national scale, but particularly on a local scale. This investigation sought to establish characteristics that describe the sustainability of local drinking water supply. We use an integrated systems approach, describing the local drinking water supply system in terms of hydrological, technical and socio-economic characteristics that determine the sustainability of a local drinking water supply system. Three cases on drinking water supply in the Netherlands are analysed. One case relates to a short-term development, that is the 2018 summer drought, and two concern long-term phenomena, that is, changes in water quality and growth in drinking water demand. The approach taken recognises that next to extreme weather events, socio-economic developments will be among the main drivers of changes in drinking water supply. Effects of pressures associated with, for example, population growth, industrial developments and land use changes, could result in limited water resource availability, deteriorated groundwater quality and growing water demand. To gain a perspective on the case study findings broader than the Dutch context, the sustainability issues identified were paired with global issues concerning sustainable drinking water supply. This resulted in a proposed set of generally applicable sustainability characteristics, each divided into five criteria describing the hydrological, technical and socio-economic sustainability of a local drinking water supply system. Elaboration of these sustainability characteristics and criteria into a sustainability assessment can provide information on the challenges and trade-offs inherent in the sustainable development and management of a local drinking water supply system.


2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Timothée R Cook ◽  
Rowan Martin ◽  
Jennifer Roberts ◽  
Henry Häkkinen ◽  
Philna Botha ◽  
...  

Abstract The frequency of extreme weather events, including heat waves, is increasing with climate change. The thermoregulatory demands resulting from hotter weather can have catastrophic impacts on animals, leading to mass mortalities. Although less dramatic, animals also experience physiological costs below, but approaching, critical temperature thresholds. These costs may be particularly constraining during reproduction, when parents must balance thermoregulation against breeding activities. Such challenges should be acute among seabirds, which often nest in locations exposed to high solar radiation and predation risk. The globally endangered bank cormorant Phalacrocorax neglectus breeds in southern Africa in the winter, giving little scope for poleward or phenological shifts in the face of increasing temperatures. Physiological studies of endangered species sensitive to human disturbance, like the bank cormorant, are challenging, because individuals cannot be captured for experimental research. Using a novel, non-invasive, videographic approach, we investigated the thermoregulatory responses of this seabird across a range of environmental temperatures at three nesting colonies. The time birds spent gular fluttering, a behaviour enhancing evaporative heat loss, increased with temperature. Crouching or standing birds spent considerably less time gular fluttering than birds sitting on nests (ca 30% less at 22°C), showing that postural adjustments mediate exposure to heat stress and enhance water conservation. Crouching or standing, however, increases the vulnerability of eggs and chicks to suboptimal temperatures and/or expose nest contents to predation, suggesting that parents may trade-off thermoregulatory demands against offspring survival. We modelled thermoregulatory responses under future climate scenarios and found that nest-bound bank cormorants will gular flutter almost continuously for several hours a day by 2100. The associated increase in water loss may lead to dehydration, forcing birds to prioritize survival over breeding, a trade-off that would ultimately deteriorate the conservation status of this species.


1970 ◽  
Vol 48 (1) ◽  
pp. 18-27 ◽  
Author(s):  
Edward M. Stricker ◽  
F. Reed Hainsworth

Previous investigations demonstrated that the water loss of rats associated with increased salivary evaporation during heat stress is derived from both intracellular and intravascular sources. The present studies indicate that sufficient dehydration of either fluid compartment will impair temperature regulation. Salivary excretion from all dehydrated rats was virtually abolished at ambient temperatures below 38–40 °C, but temperature regulation was still possible if a large temperature gradient existed between the animals and the environment. Above these ambient temperatures, where increased evaporation is essential to survival, the rate of evaporative water loss returned to normal. However, body water reservoirs in dehydrated rats were rapidly depleted, salivary evaporation could not be maintained, and survival times were shortened. In contrast, access to drinking water significantly increased thermal tolerance. These results emphasize the importance of adequate body fluid hydration for evaporative cooling through saliva spreading by rats in the heat. In addition, they indicate that allocation of body water for evaporation takes precedence over conflicting demands for water conservation during heat stress.


2008 ◽  
Vol 7 (4) ◽  
pp. 453-458
Author(s):  
Mihai Gavrilas ◽  
Gilda Gavrilas ◽  
Ovidiu Ivanov

Alloy Digest ◽  
1965 ◽  
Vol 14 (5) ◽  

Abstract LAVIN NDZ-S BRONZE is a copper-base alloy recommended as a high-strength dezincification and dealuminization resistant valve stem material in water supply systems. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on casting and machining. Filing Code: Cu-151. Producer or source: R. Lavin & Sons Inc..


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