Waste heat and electrically driven hybrid cooling systems for a high ambient temperature, off-grid application

Cooling power constitutes a large portion of the total electrical power consumption in data centers. Approximately 25%∼40% of the electricity used within a production data center is consumed by the cooling system. Improving the cooling energy efficiency has attracted a great deal of research attention. Many strategies have been proposed for cutting the data center energy costs. One of the effective strategies for increasing the cooling efficiency is using dynamic thermal management. Another effective strategy is placing cooling devices (heat exchangers) closer to the source of heat. This is the basic design principle of many hybrid cooling systems and liquid cooling systems for data centers. Dynamic thermal management of data centers is a huge challenge, due to the fact that data centers are operated under complex dynamic conditions, even during normal operating conditions. In addition, hybrid cooling systems for data centers introduce additional localized cooling devices, such as in row cooling units and overhead coolers, which significantly increase the complexity of dynamic thermal management. Therefore, it is of paramount importance to characterize the dynamic responses of data centers under variations from different cooling units, such as cooling air flow rate variations. In this study, a detailed computational analysis of an in row cooler based hybrid cooled data center is conducted using a commercially available computational fluid dynamics (CFD) code. A representative CFD model for a raised floor data center with cold aisle-hot aisle arrangement fashion is developed. The hybrid cooling system is designed using perimeter CRAH units and localized in row cooling units. The CRAH unit supplies centralized cooling air to the under floor plenum, and the cooling air enters the cold aisle through perforated tiles. The in row cooling unit is located on the raised floor between the server racks. It supplies the cooling air directly to the cold aisle, and intakes hot air from the back of the racks (hot aisle). Therefore, two different cooling air sources are supplied to the cold aisle, but the ways they are delivered to the cold aisle are different. Several modeling cases are designed to study the transient effects of variations in the flow rates of the two cooling air sources. The server power and the cooling air flow variation combination scenarios are also modeled and studied. The detailed impacts of each modeling case on the rack inlet air temperature and cold aisle air flow distribution are studied. The results presented in this work provide an understanding of the effects of air flow variations on the thermal performance of data centers. The results and corresponding analysis is used for improving the running efficiency of this type of raised floor hybrid data centers using CRAH and IRC units.

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Feeding Effects on Broiler Thermobalance During Thermoneutral and High Ambient Temperature Exposure

Poultry Science ◽

10.3382/ps.0721917 ◽

1993 ◽

Vol 72 (10) ◽

pp. 1917-1924 ◽

Cited By ~ 20

Author(s):

C.J. WIERNUSZ ◽

R.G. TEETER

Keyword(s):

Ambient Temperature ◽

High Ambient Temperature ◽

Feeding Effects ◽

Temperature Exposure

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PSVII-24 Blend of essential oils plus 25-hydroxy-vitamin-D3 as alternative to the use monensin on growth performance and dietary energetics in feedlot cattle raised under high ambient temperature

Journal of Animal Science ◽

10.1093/jas/skab235.805 ◽

2021 ◽

Vol 99 (Supplement_3) ◽

pp. 452-453

Author(s):

Daniel Mendoza-Cortés ◽

Jorge L Ramos-Méndez ◽

Adrián Félix-Bernal ◽

Alfredo Estrada-Angulo ◽

Manuel Franco ◽

...

Keyword(s):

Essential Oils ◽

Ambient Temperature ◽

Vitamin D3 ◽

Animal Health ◽

Average Daily Gain ◽

Feedlot Cattle ◽

High Ambient Temperature ◽

Energy Utilization ◽

Daily Weight Gain ◽

Final Weight

Abstract Ninety young crossbreed bulls (approximately 25% Zebu breeding with the remainder represented by continental and British breeds in various proportions, initial weight=228.04±7.06 kg) were used in a 84-day feeding trial to assess the effects of treatments in feedlot cattle fed transition diets during high ambient temperatures. Treatments consisted of a steam-flaked corn-based diets (average 1.95 Mcal ENm/kg) supplemented with: 1) 20 mg monensin/kg diet (MON, Rumensin, Elanco Animal Health, Indianapolis, IN], and 2) 100 mg of blend of essential oils /kg diet plus 0.1 mg 25-hydroxy-vitamin-D3/kg diet (EO+HyD; CRINA® Ruminants and HyD®, DSM Nutritional Products, Basel, Switzerland). Both dry matter intake (DMI) and climatic variables were measured daily and the temperature humidity index (THI) was estimated. Daily maximal THI remained over 80 during the whole trial (avg. THI = 82.67). Cattle supplemented with EO+HyD increased average daily gain in 8.7% (1.446 vs. 1.320 kg/day, P < 0.01), gain-to-fed ratio in 4.5% (0.199 vs. 0.190; P = 0.03), final weight in 10.05 kg (349.48 vs. 339.43; P = 0.04) and tended (P = 0.07) to shown greater dietary net energy (2.5%) and observed-to-expected dietary NE ratio (3%). Even when EO+HyD tended to increase (4.3%; P = 0.06) DM intake, intake pattern variation were not different (P = 0.38) between MON and EO+HyD (Figure 1). Then, difference in ADG and final BW between MON and EO+HyD was not only a reflection of difference in energy intake, was also caused by difference in efficiency of energy utilization during conditions of high ambient temperature (a reduction of 7% in the estimated increase of coefficient of maintenance by heat load). Results indicate that supplementation with a combination of essential oil blend plus 25-hydroxy-vitamin-D3 can have greater beneficial effects than supplemental monensin on daily weight gain, final weight and feed intake during initiation-transition phase of cattle raised under high ambient temperature.

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546 Management of Pediatric Pavement Burns

Journal of Burn Care & Research ◽

10.1093/jbcr/irab032.196 ◽

2021 ◽

Vol 42 (Supplement_1) ◽

pp. S121-S122

Author(s):

Syed F Saquib ◽

Paul J Chestovich ◽

Joseph T Carroll ◽

Carmen E Flores

Keyword(s):

Ambient Temperature ◽

Average Length ◽

Topical Therapy ◽

Total Body Surface Area ◽

High Ambient Temperature ◽

Unknown Etiology ◽

Oral Antibiotic ◽

Superficial Infection ◽

Plantar Aspect

Abstract Introduction Pavement burns are common in a dry high heat climate. This study reviews the etiology, management and outcome of pavement burns in children. Methods All patients age < 18 who suffered contact burns from hot pavement from Jan 1, 2014 to Dec 31, 2019 were reviewed. A total of 45 patient charts met inclusion criteria. High ambient temperature on each date, and zip code of each injury was extracted from Weather Underground (www.wunderground.com) Results In this study, 45 patients met criteria and were reviewed, of whom 27 patients (60%) were male. Average age was 3.29 years (SD 0.69), made up two discrete age groups: age under 3 (n= 40, 89%) and 14+ (n=5, 11%). 38 patients (84%) had no known medical history. All had 2nd degree burns and one patient (2%) had third degree burns. Mean total body surface area (TBSA) was 2.5% (SD 1.4%, range 0.75% to 5.5%). Burn etiology included 31 patients (69%) walking barefoot on pavement, 6 (13%) falling onto pavement, and other/unknown etiology for the remaining 8 patients (18%). 30 patients (67%) had injuries on the plantar aspect of bilateral feet, 2 (4%) to bilateral palms of hands, 4 (9%) to other parts of upper extremities and 10 (22%) to other parts of lower extremities. Thirty-four (34) patients (76%) were managed without any hospitalization. Those that were hospitalized had an average length of stay (LOS) of 2.72 days (range 1–9 days). All burns were managed non-operatively with topical therapy alone. 35 patients (78%) were managed initially with Silvadene, and 6 (13%) with bacitracin. Aquacel was utilized in 10 patients at a follow-up visit (22%). Three patients (6.7%) were treated with collagenase enzyme therapy. One patient developed a superficial infection requiring oral antibiotic therapy. There were no mortalities in this group. The high ambient temperature on date and location of each injury was 101 F (SD 1.10 F, range 73F-111F). Of the thirty that continued to follow up in clinic, the average time to the burn being 95% healed was 10.50 days (SD 8.97 days, range 2–40 days). Conclusions Pavement burns in children are partial thickness and are safely managed with topical therapy alone, with good outcomes. Patients age 3 and under are a vulnerable population and therefore at particular risk of injury.

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