Impacts of Balance Valves on Pump Energy and Control Performance in Variable Water Flow Systems

Solar Energy ◽  
2004 ◽  
Author(s):  
B. Zheng ◽  
M. Liu
Keyword(s):  
Pressure Drop ◽  
Water Flow ◽  
Pump Energy ◽  
System Control ◽  
Control Performance ◽  
Reduced Pressure ◽  
Control Valves ◽  
Partial Load ◽  
Flow Systems ◽  
Variable Water

There is no common agreement on the use of balance valves in the most popular variable water flow systems. A comprehensive theoretical analysis has been conducted to investigate the impacts of balance valves on initial cost, pump operation power, and system control performance. The investigation finds that eliminating balance valves can (1) reduce 20% to 40% pump energy consumption in a typical variable flow water system; (2) reduce the maximum pressure drop across control valves; and (3) improve pump efficiency at most partial load conditions. The reduced pressure drop across control valves improve system control performance and may allow selecting some of the control valves at lower close-off pressure. Consequently, eliminating balancing valves can also potential reduce system initial costs.

Impacts of Balancing Valves on Pump Energy and Control Performance in Variable Water Flow Systems

2005 ◽  
Vol 128 (3) ◽  
pp. 414-417 ◽  
Author(s):  
B. Zheng ◽  
M. Liu
Keyword(s):  
Water Flow ◽  
Pump Energy ◽  
System Control ◽  
Control Performance ◽  
Reduced Pressure ◽  
Control Valves ◽  
Initial Cost ◽  
Partial Load ◽  
Flow Systems ◽  
Variable Water

There is no common agreement on the use of balance valves in the most popular variable water flow systems. A comprehensive theoretical analysis has been conducted to investigate the impacts of balance valves on initial cost, pump operation power, and system control performance. The investigation finds that eliminating balance valves can (i) reduce by 20–40% pump energy consumption in a typical variable flow water system, (ii) reduce the maximum pressure drop across control valves, and (iii) improve pump efficiency at most partial load conditions. The reduced pressure drops across control valves improve system control performance and may allow selecting some control valves at lower close-off pressures. Consequently, eliminating balancing valves can also potentially reduce system initial cost.

scholarly journals Variable flow and optimization of chiller loading effect on energy saving for screw vapor compression-single effect absorption hybrid chiller plant in hospital mechanical room ‒ case study: Tehran heart hospital

2021 ◽  
Vol 22 ◽  
pp. 9
Author(s):  
Ronald Boghosian ◽  
Mostafa Mafi ◽  
Mohammad Hassan Panjeshahi ◽  
Abtin Ataei
Keyword(s):  
Energy Consumption ◽  
Energy Saving ◽  
Water Flow ◽  
Flow System ◽  
Vapor Compression ◽  
Absorption Chillers ◽  
Partial Load ◽  
Energy Consuming ◽  
Single Effect ◽  
Variable Water

Chiller plants are the most energy consuming system during summer season in residential, commercial and hospital buildings. The highly variable cooling demand of the buildings connected to a hybrid chiller plant included absorption and vapor compression chillers to achieve higher energy efficiencies is one of the important issues. Cooling load sharing strategies and apply the variable water flow system in chiller plant have a significant impact on energy consumption and consequently with more productivity and environmentally protected. This paper examines the behavior and pattern of energy consumption in a hybrid chiller plant that includes a combination of two air-cooled screw vapor compression and three single effect absorption chillers. In order to properly understand the pattern of energy consumption, an existing mechanical room in a hospital in Tehran has been studied for five months, and its energy consumption has been compared with the optimized model. The results indicate that the sequence of the chiller function and the way in which they are placed in the circuit during a partial load, is in highest importance in view point of energy saving also by Applying of variable water flow system for optimized chiller loading the more energy saving is achieved for hybrid absorption and vapor compression chiller plant.

Heat Transfer Enhancement in a Rectangular (AR = 3:1) Channel With V-Shaped Dimples

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
C. Neil Jordan ◽  
Lesley M. Wright
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Liquid Crystal ◽  
Pressure Drop ◽  
Heat Transfer Enhancement ◽  
Thermal Performance ◽  
Secondary Flows ◽  
Transfer Enhancement ◽  
Reduced Pressure

An alternative to ribs for internal heat transfer enhancement of gas turbine airfoils is dimpled depressions. Relative to ribs, dimples incur a reduced pressure drop, which can increase the overall thermal performance of the channel. This experimental investigation measures detailed Nusselt number ratio distributions obtained from an array of V-shaped dimples (δ/D = 0.30). Although the V-shaped dimple array is derived from a traditional hemispherical dimple array, the V-shaped dimples are arranged in an in-line pattern. The resulting spacing of the V-shaped dimples is 3.2D in both the streamwise and spanwise directions. A single wide wall of a rectangular channel (AR = 3:1) is lined with V-shaped dimples. The channel Reynolds number ranges from 10,000–40,000. Detailed Nusselt number ratios are obtained using both a transient liquid crystal technique and a newly developed transient temperature sensitive paint (TSP) technique. Therefore, the TSP technique is not only validated against a baseline geometry (smooth channel), but it is also validated against a more established technique. Measurements indicate that the proposed V-shaped dimple design is a promising alternative to traditional ribs or hemispherical dimples. At lower Reynolds numbers, the V-shaped dimples display heat transfer and friction behavior similar to traditional dimples. However, as the Reynolds number increases to 30,000 and 40,000, secondary flows developed in the V-shaped concavities further enhance the heat transfer from the dimpled surface (similar to angled and V-shaped rib induced secondary flows). This additional enhancement is obtained with only a marginal increase in the pressure drop. Therefore, as the Reynolds number within the channel increases, the thermal performance also increases. While this trend has been confirmed with both the transient TSP and liquid crystal techniques, TSP is shown to have limited capabilities when acquiring highly resolved detailed heat transfer coefficient distributions.

Gas holdup and pressure drop for air-water flow through plate bubble columns

1986 ◽  
Vol 64 (3) ◽  
pp. 387-392 ◽  
Author(s):  
B. H. Chen ◽  
N. S. Yang ◽  
A. F. Mcmillan
Keyword(s):  
Pressure Drop ◽  
Water Flow ◽  
Gas Holdup ◽  
Bubble Columns ◽  
Flow Through

Optimizing the performance of hemispheric solar still using nano-ZnO with cooling the glassy cover at a variable water flow rate

2021 ◽  
Author(s):  
Mohammed El Hadi Attia ◽  
Abd Elnaby Kabeel ◽  
S. A. El-Agouz ◽  
El Mir Mabrouk Lassaad ◽  
Ravishankar Sathyamurthy ◽  
...  
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Water Flow Rate ◽  
Solar Still ◽  
Nano Zno ◽  
Variable Water

The Fluid Power Control Performance Comparison Study of Two-Type ER Valve Based on FLUENT

2012 ◽  
Vol 472-475 ◽  
pp. 1989-1994
Author(s):  
Shi Sha Zhu ◽  
Liu Tao
Keyword(s):  
Pressure Drop ◽  
Power Control ◽  
Parallel Plate ◽  
Control Volume ◽  
Flow Simulation ◽  
Control Valve ◽  
Performance Comparison ◽  
Fluid Power ◽  
Control Performance ◽  
Plate Type

The current flow and pressure drop of ER valve which is a new type power control valve could be adjusted by the electric field signal directly .In this paper, the fluid power control performance of concentric cylindrical ER valve and parallel plate-type ER valve based on ER principal is comparative studied .First power control equation has been analysed, and then flow simulation of internal flow field of ER valve has been taken based on FLUENT software. The results show that with the increasing of the strength of excitation field, the flow through the two different type of ER valve decreases, the pressure drop between import and export is even greater; and the fluid power control performance of parallel plate-type ER valve is superior to concentric cylindrical ER valve under the same control volume.

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