scholarly journals Control Strategies in Multi-Zone Air Conditioning Systems

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 347 ◽  
Author(s):  
Behzad Rismanchi ◽  
Juan Zambrano ◽  
Bryan Saxby ◽  
Ross Tuck ◽  
Mark Stenning
Keyword(s):  
Air Conditioning ◽  
New Technologies ◽  
Control Strategies ◽  
Efficient Solutions ◽  
Indoor Environments ◽  
Commercial Building ◽  
Thermal Discomfort ◽  
Variable Air Volume ◽  
Air Volume ◽  
Air Conditioning Systems

In a commercial building, a significant amount of energy is used by the ventilation systems to condition the air for the ‎indoor environments to satisfy the required quantity (temperature ‎and humidity) and quality (amount of fresh air). For many years, Variable Air Volume ‎‎(VAV) systems have been considered as the most efficient solutions by balancing the airflow volume based on the demand making them energy efficient when compared with the traditional Constant Air Volume (CAV) systems. However, the setpoints in VAV systems are ‎often misread by the sensors due to stratification and formation of pollutant pockets and ‎responding to design levels that overestimate the real-time demand conditions, which result in ‎waste of energy, thermal discomfort and unhealthy air. In general, VAV devices are expensive, complicated and prone to failures and ‎they are used only in medium and large projects. More recently, new technologies have evolved to solve this issue. In one of the new solutions, VAV motors terminals are replaced with flaps which are simpler and less expensive thus, they can be implemented ‎in a wider range of projects. In systems, balancing and supplying the optimal airflow ‎to reduce the energy consumption while delivering ideal thermal and Indoor Air Quality (IAQ) levels are the ‎main challenges. In this paper, a comparison of the recent technologies with traditional VAV systems is presented to be used as a guild line for researchers and designers in the field of Heating Ventilation Air Conditioning (HVAC)‎.

Comparative Energy Analysis of VRF and VAV Systems Under Cooling Mode

2009 ◽  
Author(s):  
Jaeyoon Koh ◽  
John Z. Zhai ◽  
Jessica A. Rivas
Keyword(s):  
Energy Cost ◽  
Air Conditioning ◽  
Energy Analysis ◽  
Commercial Building ◽  
Energy Usage ◽  
Cooling Mode ◽  
Variable Air Volume ◽  
Air Volume ◽  
Electrical Demand ◽  
Air Conditioning Systems

Variable refrigerant flow (VRF) or variable refrigerant volume (VRV) systems provide many benefits over traditional air-conditioning systems, with great potential to decrease energy cost and increase thermal comfort in buildings. This paper presents a method to size and select VRF systems and to compute its annual energy consumption. The study compares the cooling energy usage of a VRF system against a conventional chiller-based variable-air-volume (VAV) system and a packaged VAV (PVAV) system for a typical light commercial building. The results reveal that the peak electrical demand of the VRF system for the cooling season is about 60% of the chiller-based VAV system and 70% of the packaged VAV systems, and the operating energy usage is about 53% of the chiller-based VAV system and 60% of the packaged VAV system for the building studied.

scholarly journals Feasibility study for the use of variable air volume systems for office buildings

2021 ◽  
Vol 36 ◽  
pp. 62-79
Author(s):  
A. Moskvitina ◽  
M.  Shyshyna ◽  
M. Korchminskyi
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Carbon Dioxide Emissions ◽  
Air Conditioning ◽  
Office Buildings ◽  
Operating Costs ◽  
Gas Emissions ◽  
Variable Air Volume ◽  
Air Volume ◽  
Air Conditioning Systems

The main factor contributing to greenhouse gas emissions is the building up of the surrounding area. Studies have shown that buildings globally consume 30-40 % of energy use and release 40-50 % of global carbon dioxide emissions. Among all systems in houses, heating, ventilation and air conditioning (HVAC) systems are by far the most energy intensive. They consume approximately 50 % of the total energy demand of buildings. However, the systems are some of the most important systems in today's buildings. The number of these systems that are being installed has increased dramatically over the past few years. This is mainly due to the increasing demands for thermal energy, comfort and climate change. This paper presents a feasibility and ecology study between two ventilation or air-conditioning systems: constant air volume (CAV) and variable air volume (VAV). One of the purposes of this work is to determine the energy costs for each of the systems. An air conditioning system that saves operating costs usually requires a large initial investment. In this case, engineers must decide whether it is worth paying the additional upfront costs for a system that has lower operating costs. Despite the low attractiveness from the point of view of the investor, the VAV systems reduce the amount of greenhouse gas emissions and the amount of energy resources for servicing the commercial sector. Such system have less metal consumption. Thus, the cost of metal processing is also reduced. The results of this study can contribute to the future selection of ventilation systems, as well as contribute to the design and improvement of the systems under study. Energy saving is one of the main reasons why VAV systems are very popular today for the design of ventilation and air conditioning systems for office buildings and in many industries abroad. With these systems, the volume of transported air is reduced as soon as the operating load falls below the maximum projected load. The calculation of emissions of harmful substances into the environment was made while ensuring the operation of CAV and VAV systems.

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

2008 ◽  
Vol 12 (3) ◽  
pp. 15-32 ◽  
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.

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