Experimental study of the pressure reset control strategy for energy-efficient fan operation

This study aimed to develop a new concept for an air terminal device for a VAV (variable air volume) ventilation system that would improve overall ventilation efficiency under a varying air supply volume. In VAV systems, air volume is modified according to the thermal load in each ventilated zone. However, lowering the airflow may cause a lack of proper air distribution and lead to the degradation of hygienic conditions. To combat this phenomenon, an air terminal device with an adapting geometry to stabilize the air throw, such that it remains constant despite the changing air volume supplied through the ventilation system, was designed and studied. Simulations that were performed using the RNG k–ε model in the ANSYS Fluent application were later validated on a laboratory stand. The results of the study show that, when using the newly proposed terminal device with an adaptive geometry, it is possible to stabilize the air throw. The thermal comfort parameters such as the PMV (predicted mean vote) and PPD (predicted percentage of dissatisfied) proved that thermal comfort was maintained in a person-occupied area regardless of changing airflow though the ventilation system.

Download Full-text

Complementary Ventilation Design Method for a Highway Twin-Tunnel Based on the Compensation Concept

Mathematical Problems in Engineering ◽

10.1155/2018/2393272 ◽

2018 ◽

Vol 2018 ◽

pp. 1-13 ◽

Cited By ~ 1

Author(s):

Lunlei Chai ◽

Xing Wang ◽

Xingbo Han ◽

Jing Song ◽

Ping Lei ◽

...

Keyword(s):

Energy Consumption ◽

Energy Efficient ◽

Design Method ◽

Ventilation System ◽

Current Method ◽

Efficient Design ◽

Improved Method ◽

Twin Tunnel ◽

Air Volume ◽

Volume Ventilation

Based on the compensation concept, an improved method for twin-tunnel complementary ventilation design considering differences in key pollutants in the uphill and downhill tunnels was proposed. The results demonstrate that the scheme developed using the improved method is more energy efficient when the energy consumption of the interchange channel is included. Here, a larger design of air volume is allocated to the uphill tunnel, and the admissible pollutant concentration for its exits. The complementary ventilation system of the Qingniling Tunnel, Dabieshan Tunnel, and Lianghekou Tunnel was redesigned for long-term performance using the improved method, and the resulting scheme was compared to that designed using the current method in terms of the total required air volume, interchange air volume, ventilation effects, and energy consumption. The results show that these factors in improved method are significantly smaller than that of the current method with an allowable reduction of ventilation effects. Moreover, the total airflow required in the Qingniling Tunnel was reduced from 889.31 to 796.74 m3/s, with a decrease rate of 10.4%; the interchange air volume was reduced from 203 to 175 m3/s, and the estimated energy consumption was decreased from 2760 to 2065.9 kW. This represents a 26% improvement in energy efficiency. The proposed method can provide a reference for the energy efficient design of ventilation systems in extra-long highway tunnels.

Download Full-text

Research on a hierarchical air balancing control method of variable air volume ventilation system

Building and Environment ◽

10.1016/j.buildenv.2020.106710 ◽

2020 ◽

Vol 175 ◽

pp. 106710

Author(s):

Hui Cai ◽

Can Cui ◽

Xin Zhang ◽

Wenjian Cai ◽

Jinyang Dai

Keyword(s):

Control Method ◽

Ventilation System ◽

Variable Air Volume ◽

Air Volume ◽

Volume Ventilation ◽

Balancing Control

Download Full-text

Energy and Buildings ◽

10.1016/j.enbuild.2016.12.080 ◽

2017 ◽

Vol 139 ◽

pp. 72-77 ◽

Cited By ~ 12

Author(s):

Samira Rahnama ◽

Alireza Afshari ◽

Niels Christian Bergsøe ◽

Sasan Sadrizadeh

Keyword(s):

Experimental Study ◽

Control Strategy ◽

Energy Efficient ◽

Reset Control

Download Full-text

Optimal Control Strategy for Variable Air Volume Air-Conditioning Systems Using Genetic Algorithms

Sustainability ◽

10.3390/su11185122 ◽

2019 ◽

Vol 11 (18) ◽

pp. 5122 ◽

Cited By ~ 3

Author(s):

Nam-Chul Seong ◽

Jee-Heon Kim ◽

Wonchang Choi

Keyword(s):

Optimal Control ◽

Genetic Algorithms ◽

Control Strategy ◽

Air Conditioning ◽

Static Pressure ◽

Hvac System ◽

Total Energy Consumption ◽

Optimal Control Strategy ◽

Variable Air Volume ◽

Air Volume

This study is aimed at developing a real-time optimal control strategy for variable air volume (VAV) air-conditioning in a heating, ventilation, and air-conditioning (HVAC) system using genetic algorithms and a simulated large-scale office building. The two selected control variables are the settings for the supply air temperature and the duct static pressure to provide optimal control for the VAV air-conditioning system. Genetic algorithms were employed to calculate the optimal control settings for each control variable. The proposed optimal control conditions were evaluated according to the total energy consumption of the HVAC system based on its component parts (fan, chiller, and cold-water pump). The results confirm that the supply air temperature and duct static pressure change according to the cooling load of the simulated building. Using the proposed optimal control variables, the total energy consumption of the building was reduced up to 5.72% compared to under ‘normal’ settings and conditions.

Download Full-text

Energy efficient fuzzy based combined variable refrigerant volume and variable air volume air conditioning system for buildings

Applied Energy ◽

10.1016/j.apenergy.2009.08.013 ◽

2010 ◽

Vol 87 (4) ◽

pp. 1158-1175 ◽

Cited By ~ 50

Author(s):

R. Karunakaran ◽

S. Iniyan ◽

Ranko Goic

Keyword(s):

Energy Efficient ◽

Air Conditioning ◽

Air Conditioning System ◽

Variable Air Volume ◽

Air Volume

Download Full-text

Energy performance analysis of Region of Peel Headquarters Building as a sustainable building using the "Carrier HAP", "eQUEST" simulation program and "RETScreen" cost analysis program

10.32920/ryerson.14647131 ◽

2021 ◽

Author(s):

Afzal Siraj Siddique

Keyword(s):

Heat Pump ◽

Energy Efficient ◽

Water Source ◽

Building Energy ◽

Open Loop ◽

Base Case ◽

Hvac System ◽

Variable Air Volume ◽

Air Volume ◽

Energy Efficient Building

The principles of building energy simulation and its relationship with heating and cooling energy calculation help to make an integrated evaluation of building energy consumption. This is used to achieve a better and more energy efficient building. The sensitivity analysis of energy efficient HVAC design was used to create an energy efficient Peel Region Headquarters Building. An energy audit was conducted on the existing building to establish the Base Case Model "Peel Region Headquarters Building" to determine its annual energy consumption across all current usage. To reduce the total energy cost of the Base Case Model, different HVAC Systmes were investigated to analyze their energy-based performance and impact on the Greehouse Gas Emission (GHG). The sensitivity analysis was conducted using two whole building simulation programs, "Carrier HAP" and "eQUEST", with three different air systems, namely, "2-Fan Dual Duct Variable Air Volume System", "1-Fan Dual Duct Variable Air Volume System" and "1-Fan Dual Duct Variable Air Volume System with two Rooftop Packaged HVAC System'. Three different types of heat pumps, namely, Open Loop Water Source Heat Pump, Closed Loop Water Source Heat Pump, and Ground Source Heat Pump, were used to determine the efficiency and viability of the three proposed HVAC System with the existing infrastructure. RETScreen International Clean Energy Project Analysis Software (Version 4) was used to evaluate the energy production and savings, life-cycle costs, emission reductions and financial viability. MNECB/CBIP and ASHRAE 90.1 (2004) Building Compliance Program was used for determining the key elements for analyzing the building components and for providing recommendations for an energy efficient building. The improvement from the conventional HVAC System to implementation of an Open Loop Water Source Heat Pump resulted in 75% energy cost savings for the Peel Region Headquarters Building. The percentage contribution of CO₂ was reduced by 78%.

Download Full-text

Experimental analysis of fuzzy controlled energy efficient demand controlled ventilation economizer cycle variable air volume air conditioning system

Thermal Science ◽

10.2298/tsci0803015r ◽

2008 ◽

Vol 12 (3) ◽

pp. 15-32 ◽

Cited By ~ 4

Author(s):

Parameshwaran Rajagopalan ◽

Karunakaran Rajasekaran ◽

Senthilkumar Alagarsamy ◽

S. Iniyan ◽

Mohal Lal

Keyword(s):

Fuzzy Logic ◽

Energy Efficient ◽

Air Conditioning ◽

Test Results ◽

Air Conditioning System ◽

Variable Air Volume ◽

Controlled Ventilation ◽

Air Volume ◽

Demand Controlled Ventilation ◽

Air Conditioning Systems

In the quest for energy conservative building design, there is now a great opportunity for a flexible and sophisticated air conditioning system capable of addressing better thermal comfort, indoor air quality, and energy efficiency, that are strongly desired. The variable refrigerant volume air conditioning system provides considerable energy savings, cost effectiveness and reduced space requirements. Applications of intelligent control like fuzzy logic controller, especially adapted to variable air volume air conditioning systems, have drawn more interest in recent years than classical control systems. An experimental analysis was performed to investigate the inherent operational characteristics of the combined variable refrigerant volume and variable air volume air conditioning systems under fixed ventilation, demand controlled ventilation, and combined demand controlled ventilation and economizer cycle techniques for two seasonal conditions. The test results of the variable refrigerant volume and variable air volume air conditioning system for each techniques are presented. The test results infer that the system controlled by fuzzy logic methodology and operated under the CO2 based mechanical ventilation scheme, effectively yields 37% and 56% per day of average energy-saving in summer and winter conditions, respectively. Based on the experimental results, the fuzzy based combined system can be considered to be an alternative energy efficient air conditioning scheme, having significant energy-saving potential compared to the conventional constant air volume air conditioning system.

Download Full-text

Experimental Study on the Optimal Running of the Refrigeration Dehumidifier with Variable Air Volume

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.271-272.645 ◽

2012 ◽

Vol 271-272 ◽

pp. 645-649

Author(s):

Liang Kai Fan ◽

Li Yuan ◽

Shi Bin Geng ◽

Hua Wang

Keyword(s):

Experimental Study ◽

Relative Humidity ◽

Variable Air Volume ◽

Air Volume ◽

Orthogonal Experiments

Studies the influence of air volume, temperature and relative humidity on the SMER of a certain type dehumidifier by orthogonal experiments. The experiment result shows that the relative humidity has more influence on the most SMER than the temperature does.

Download Full-text