System Performance Analysis of Overlap Coupled Control Units

2001 ◽  
Author(s):  
Mingsheng Liu ◽  
Jinrong Wang
Keyword(s):  
Energy Consumption ◽  
Peak Load ◽  
Control Unit ◽  
Simulation Models ◽  
Energy Performance ◽  
Energy Simulation ◽  
Variable Air Volume ◽  
System Parameters ◽  
Air Volume ◽  
Control Units

Abstract The overlap coupled control unit is widely used in hotels, dormitory buildings, hospitals, and office buildings. Energy simulation models are developed to assess changes in energy consumption and humidity levels due to changes in various system parameters. The simulation results show that the energy consumption of the overlap unit is 3 to 5 times higher than the optimal energy consumption. To improve the energy performance, the following measures are recommended: (1) use the variable air volume technique; (2) balance total airflow based on actual peak load; and (3) replace overlap with humidistat. Quick open valves are also found to improve relative humidity control.

Energy Performance Analysis of Coupled Control Units With Both Thermostat and Humidistat

2001 ◽  
Author(s):  
Mingsheng Liu ◽  
Jinrong Wang
Keyword(s):  
Computer Simulation ◽  
Thermal Energy ◽  
Control Unit ◽  
Simulation Models ◽  
Energy Performance ◽  
Variable Air Volume ◽  
Air Volume ◽  
Control Units ◽  
Simulation Results ◽  
Computer Simulation Models

Abstract The coupled control unit is widely used in hotels, dormitory buildings, hospitals, and office buildings. Computer simulation models are developed to analyze the thermal energy performance of the coupled control units. Simulation results indicate that excessive airflow significantly increases thermal and fan power consumption. The variable air volume technique or the return air by-pass can be used to improve the energy performance of the coupled control units. The humidistat should be properly set and located to avoid excessive thermal energy consumption.

The Energy Performance Of A University Library Building

1994 ◽  
pp. 59-68
Author(s):  
Mat Nawi Wan Hassan ◽  
Mohd.Yusoff Senawi ◽  
Hartini Omar
Keyword(s):  
Air Conditioning ◽  
Operating Cost ◽  
Building Energy ◽  
Energy Performance ◽  
Energy Simulation ◽  
Building Energy Simulation ◽  
Variable Air Volume ◽  
Air Volume ◽  
Lighting Intensity ◽  
Glazed Facade

The energy performance of a four-storey library (PSZ) building of Universiti Teknologi Malaysia (UTM) has been simulated using a microcomputer-based building energy simulation program, SHEAP. The simulation results give a comparative estimate of the potential annual savings for nine parameters. Significant savings (greater than 3.7% of RM 815,680 in operating cost) can result from the use of a Variable Air Volume (VAV) system, reduced air-conditioning times and reduced electrical lighting intensity. A 25% glazed-facade can contribute about 1% in saving,while the other parameters contribute less than 0.2% in savings to be of any significance.

Energy Performance Analysis of Coupled-Control Units With Both Thermostat and Humidistat

2005 ◽  
Vol 127 (1) ◽  
pp. 65-69 ◽  
Author(s):  
Mingsheng Liu ◽  
Jinrong Wang
Keyword(s):  
Energy Consumption ◽  
Relative Humidity ◽  
Thermal Energy ◽  
Simulation Models ◽  
Energy Performance ◽  
Set Point ◽  
Control Units ◽  
Improvement Measures ◽  
Potential Improvement ◽  
Cooling Coil

Coupled control units typically condition a single zone with constant air volume. A thermostat controls the heating valve or cooling valve when the room relative humidity is below the set point. When the room relative humidity is higher than the set point, a humidistat controls the cooling coil to dehumidify air and the thermostat controls the heating coil to maintain room temperature. Theoretical modeling is performed to investigate the energy performance of coupled control units and potential improvement measures. The study shows that the annual thermal energy consumption of the coupled-control units is up to four times higher than the optimal thermal energy consumption. Thermal energy consumption can be reduced by (a) eliminating excessive airflows, (b) minimizing valve leakages, and (c) modulating airflows with a zone sensible load. This paper presents the simulation models and results and discusses improvement measures.

scholarly journals The Analysis for Energy Consumption of Marine Air Conditioning System Based on VAV and VWV

2018 ◽  
Vol 38 ◽  
pp. 04012
Author(s):  
Sai Feng Xu ◽  
Xing Lin Yang ◽  
Zou Ying Le
Keyword(s):  
Energy Consumption ◽  
Energy Saving ◽  
Air Conditioning ◽  
Water Volume ◽  
Pump System ◽  
Air Conditioning System ◽  
Variable Air Volume ◽  
Air Volume ◽  
Marine Air ◽  
Variable Water

For ocean-going vessels sailing in different areas on the sea, the change of external environment factors will cause frequent changes in load, traditional ship air-conditioning system is usually designed with a fixed cooling capacity, this design method causes serious waste of resources. A new type of sea-based air conditioning system is proposed in this paper, which uses the sea-based source heat pump system, combined with variable air volume, variable water technology. The multifunctional cabins’ dynamic loads for a ship navigating in a typical Eurasian route were calculated based on Simulink. The model can predict changes in full voyage load. Based on the simulation model, the effects of variable air volume and variable water volume on the energy consumption of the air-conditioning system are analyzed. The results show that: When the VAV is coupled with the VWV, the energy saving rate is 23.2%. Therefore, the application of variable air volume and variable water technology to marine air conditioning systems can achieve economical and energy saving advantages.

Development and Validation of Online Parameter Estimation for HVAC Systems

2003 ◽  
Vol 125 (3) ◽  
pp. 324-330 ◽  
Author(s):  
Jin Wen ◽  
Theodore F. Smith
Keyword(s):  
Energy Efficiency ◽  
Parameter Estimation ◽  
Hvac Systems ◽  
Recursive Least Squares ◽  
Volume Discharge ◽  
Thermal Loads ◽  
Variable Air Volume ◽  
Improve Energy Efficiency ◽  
System Parameters ◽  
Air Volume

Improving the energy efficiency of buildings by examining their heating, ventilating, and air-conditioning (HVAC) systems represents an opportunity. To improve energy efficiency, to increase occupant comfort, and to provide better system operation and control algorithms for these systems, online estimation of system parameters, including system thermophysical parameters and thermal loads, is desirable. Several reported studies have presented simulation results and assumed that the thermal loads are known. A difficulty in HVAC system parameter estimation is that most HVAC systems are nonlinear, have multiple and time varying parameters, and require an estimate of the thermal loads for a building zone. In this study, building zones and variable-air-volume units are modeled. The system parameters including the thermal loads are estimated using the recursive-least-squares method with a variable forgetting factor. The sensitivity of the estimation results to different factors is examined. The estimated parameters are used to predict the zone and variable-air-volume-discharge-air temperatures. Several experiments are used to validate the prediction results. The comparisons show good agreement between the experiments and the prediction results.

Analysis of Running Energy Consumption of Fresh Air Cooling Systems

Solar Energy ◽  
2005 ◽  
Author(s):  
Jianing Zhao ◽  
Jun Guo ◽  
Weimeng Sun
Keyword(s):  
Energy Consumption ◽  
Total Energy ◽  
Cooling System ◽  
Air Cooling ◽  
Total Energy Consumption ◽  
Cooling Systems ◽  
Variable Air Volume ◽  
Air Volume ◽  
Air System ◽  
Different Seasons

Utilization of renewable energy becomes more and more attractive and crucial for sustainable buildings. A cooling system, using outdoor fresh air and combining with the conventional all-air system or running along during different seasons, is discussed in this study. Running energy consumption of this system is analyzed by a mathematical model using the Genetic Algorithm (GA) combined with the traditional Lagrange method. To evaluate and apply this new system, energy consumption of the chiller unit, water and air sub-systems, as well as the total energy consumption of such a system is compared with that of the conventional all-air system. Consequently, the total energy consumption is selected as the criterion of energy efficiency. The results show that the cooling system bears considerably energy efficient, and that it reduces energy consumption at least 14% and 12%, compared with the constant air volume and variable air volume system, respectively.

scholarly journals An Occupant-Based Energy Consumption Model for User-Focused Design of Residential Buildings

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Toufic Zaraket ◽  
Bernard Yannou ◽  
Yann Leroy ◽  
Stéphanie Minel ◽  
Emilie Chapotot
Keyword(s):  
Energy Consumption ◽  
Residential Buildings ◽  
Energy Performance ◽  
Energy Simulation ◽  
Simulation Tools ◽  
Modeling Methodology ◽  
Management Processes ◽  
Proposed Model ◽  
Energy Consumption Model ◽  
Industrial Energy

Occupants' behavior exerts a significant influence on the energy performance of residential buildings. Industrial energy simulation tools often account for occupants' as monolithic elements with standard averaged energy consumption profiles. Predictions yielded by these tools can thus deviate dramatically from reality. This paper proposes an activity-based model for forecasting energy and water consumption of households and discusses how such an occupant-focused model may integrate a user-focused design of residential buildings. A literature review is first presented followed by a brief recall of the proposed modeling methodology and a sample of simulation results. The possible integration of the proposed model into the design and energy management processes of residential buildings is then demonstrated through a number of use cases.

Energy Performance Simulation Study on VAV Air Condition System at SPSU Campus Office Building with EnergyPlus

2013 ◽  
Vol 361-363 ◽  
pp. 249-252 ◽  
Author(s):  
Gui Chen Zhang
Keyword(s):  
Cooling Rate ◽  
Energy Performance ◽  
Department Of Energy ◽  
Office Building ◽  
Variable Air Volume ◽  
Outdoor Climate ◽  
Air Volume ◽  
Building Models ◽  
The Usa ◽  
Condition Systems

Based on the air condition systems theorem, by EnergyPlus7.0 the office building models were built up with the variable air volume (VAV) and constant air volume (CAV) systems separately at SPSU campus in the USA. The weather datum from Department of Energy US were used to simulate the energy consumption performance both daily and annually. Results show that the VAV system saves the sensible cooling rate 19.25% compared with the CAV one in the hottest day. The VAV system saves the sensible cooling rate 8.95% and reduces the outdoor infiltration sensible heat gain about 35.06% yearly. The VAV terminal-damper position doesnt change linearly as the outdoor climate temperature for the complex system in heating, ventilating, and air-conditioning (HVAC). Though the outdoor temperature is the same, the system sensible cooling rate is greatly different in autumn and spring day.

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