Terminal Box Minimum Airflow Optimization of Single Duct Air Handling Units

2007 ◽  
Author(s):  
YoungHum Cho ◽  
Gang Wang ◽  
Mingsheng Liu
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
Thermal Environment ◽  
Variable Air Volume ◽  
Heating And Cooling ◽  
Air Handling Unit ◽  
Simultaneous Heating ◽  
Save Energy ◽  
Heating Loads ◽  
Simultaneous Heating And Cooling

Terminal boxes control space conditions in variable air volume (VAV) air-handling unit (AHU) systems. Terminal boxes either modulate airflow with a control damper or adjust discharge air temperature with a reheat coil. Terminal boxes will have a significant amount of simultaneous heating and cooling and AHUs will consume more fan power if the minimum airflow is higher than required. On the other hand, conditioned space will have indoor air quality (IAQ) problems with less air circulation if the minimum airflow is less than required. The objective of this study is to optimize the minimum airflow ratio to improve thermal environment and save energy consumption. In this study, the problem of current fixed minimum airflow ratio of terminal box is analyzed and variable minimum airflow ratio as an alternative is suggested. The results of this study show that variable minimum airflow ratio can stably maintain the set room air temperature and reduce energy consumption for varying heating loads compared to the conventional fixed minimum airflow ratio.

Variable Air Volume System Application in Museums

2007 ◽  
Author(s):  
Zhan Wang ◽  
Bin Zheng ◽  
Wenlong Xu ◽  
Gang Wang ◽  
Mingsheng Liu
Keyword(s):  
Energy Consumption ◽  
System Control ◽  
Variable Air Volume ◽  
Heating And Cooling ◽  
Air Volume ◽  
Variable Frequency Drives ◽  
Air Handling Units ◽  
Simultaneous Heating ◽  
Simultaneous Heating And Cooling ◽  
Cooling Loads

Relative humidity and temperature control is key in museums, galleries, libraries and archives. Normally constant volume (CV) air handling units (AHUs) with reheat coils are applied in these buildings. Setting a low supply air temperature limits the highest humidity level; however, reheat coils have to be used to maintain space temperature due to constant supply airflow. As a result, simultaneous heating and cooling exists with excessive energy consumption. It is well known that variable air volume (VAV) technologies can reduce simultaneous heating and cooling as well as fan power. This paper presents the detail VAV system retrofit for the existing CV system, control sequence development and system performance evaluation in a museum facility at Omaha, Nebraska. Variable Frequency Drives (VFDs) were installed for the supply fan on the AHUs. Space humidity and temperature, heating and cooling energy consumption, and fan power were measured. The measurements showed that the space humidity and temperature was maintained within the required range under VAV operation while the reheat consumption was reduced by up to 85% and the fan power consumption was reduced by 90% under partial cooling loads.

Effect of Minimum Airflow Setting of VAV Unit on Building Energy Consumption under Korean Climatic Condition

2012 ◽  
Vol 450-451 ◽  
pp. 1435-1439
Author(s):  
Kwang Ho Lee ◽  
Kyung Il Chin ◽  
Jong Ho Yoon
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
Variable Air Volume ◽  
Unit System ◽  
Energy Impact ◽  
Heating And Cooling ◽  
Significant Difference ◽  
Gas Consumption ◽  
Forced Air ◽  
The Impact

Variable Air Volume (VAV) unit system is one of the commonly used forced-air heating and cooling systems in office buildings. It controls the airflow with the discharge air temperature fixed for cooling, while the discharge air temperature is adjusted with the airflow fixed at the minimum for heating. This study presents the simulation of conventional VAV unit system performance applied in the typical office building prototype. Each VAV unit has the minimum airflow setting for the ventilation purpose and its impact on the energy consumption is significant. The aim of this study is to evaluate the energy impact of the minimum airflow setting of VAV box using EnergyPlus ver. 6.0 software platform. The energy result breakdown of three model cases is discussed: minimum airflow fraction setting of 10%, 20% and 30%. As a result, the minimum airflow setting has significant impact on the reheat energy and thus the annual boiler gas consumption shows significant difference among each simulation case. Monthly heating energy profile is also discussed for the better understanding of the impact of different minimum fractions on the heating energy.

Energy efficient refrigeration system with simultaneous heating and cooling

2021 ◽  
Author(s):  
P. Nikhil Babu ◽  
D. Mohankumar ◽  
P. Manoj Kumar ◽  
M. Makeshkumar ◽  
M. Gokulnath ◽  
...  
Keyword(s):  
Energy Efficient ◽  
Refrigeration System ◽  
Heating And Cooling ◽  
Simultaneous Heating ◽  
Simultaneous Heating And Cooling

scholarly journals Energy-saving potential of intermittent heating system: Influence of composite phase change wall and optimization strategy

2020 ◽  
pp. 014459872096921
Author(s):  
Yanru Li ◽  
Enshen Long ◽  
Lili Zhang ◽  
Xiangyu Dong ◽  
Suo Wang
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Phase Change ◽  
Air Temperature ◽  
Indoor Air ◽  
Thermal Environment ◽  
Optimization Strategy ◽  
Indoor Thermal Environment ◽  
Indoor Thermal Comfort ◽  
Intermittent Heating

In the Yangtze River zone of China, the heating operation in buildings is mainly part-time and part-space, which could affect the indoor thermal comfort while making the thermal process of building envelope different. This paper proposed to integrate phase change material (PCM) to building walls to increase the indoor thermal comfort and attenuate the temperature fluctuations during intermittent heating. The aim of this study is to investigate the influence of this kind of composite phase change wall (composite-PCW) on the indoor thermal environment and energy consumption of intermittent heating, and further develop an optimization strategy of intermittent heating operation by using EnergyPlus simulation. Results show that the indoor air temperature of the building with the composite-PCW was 2–3°C higher than the building with the reference wall (normal foamed concrete wall) during the heating-off process. Moreover, the indoor air temperature was higher than 18°C and the mean radiation temperature was above 20°C in the first 1 h after stopping heating. Under the optimized operation condition of turning off the heating device 1 h in advance, the heat release process of the composite-PCW to the indoor environment could maintain the indoor thermal environment within the comfortable range effectively. The composite-PCW could decrease 4.74% of the yearly heating energy consumption compared with the reference wall. The optimization described can provide useful information and guidance for the energy saving of intermittently heated buildings.

scholarly journals Yearly Cost Saving by Using Enthalpy Heat Exchanger During Cooling and Heating

2020 ◽  
Vol 328 ◽  
pp. 01014
Author(s):  
Kamil Križo ◽  
Andrej Kapjor ◽  
Martin Vantúch
Keyword(s):  
Energy Consumption ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Building Energy ◽  
Sensible Heat ◽  
Oxygen Level ◽  
Optimal Temperature ◽  
Air Handling Unit ◽  
Save Energy ◽  
Yearly Cost

Fresh air has to be constantly supplied to the building by air handling unit, where supplied air is mixed with inside air and optimal temperature, oxygen level is adjusted and level of dust and smoke is reduced. Supply air demand of the building is determined according to number of persons in the room, room area and regulations. Necessity of ventilation rely in supplying room with oxygen, cleaning the air, adjusting temperature and moisture and reduction of odours, gases, dust, bacteria and viruses. Achieving optimal properties of supply air creates huge portion of building energy consumption. To save energy during ventilation, standard air to air sensible heat exchangers are used. They purpose is to recover sensible heat from exhaust air and at the same time avoid contamination of supply air. Drawback of these types of exchangers is limit of recovering moisture, therefore huge portion of energy in form of latent heat is lost. On top of classical plate air to air heat exchanger, enthalpy heat exchanger allows to exchange latent as well as sensible heat [1].

scholarly journals Full-scale operation of a novel two-pipe active beam system for simultaneous heating and cooling of office buildings

2019 ◽  
Vol 111 ◽  
pp. 01073
Author(s):  
Alessandro Maccarini ◽  
Göran Hultmark ◽  
Niels C. Bergsøe ◽  
Alireza Afshari
Keyword(s):  
Room Temperature ◽  
Energy Performance ◽  
Physical Parameters ◽  
Heating And Cooling ◽  
System A ◽  
A Value ◽  
Beam System ◽  
Simultaneous Heating ◽  
Simultaneous Heating And Cooling ◽  
Cooling Loads

This paper presents an investigation on the operation of a novel active beam system installed in an office building located in Jönköping, Sweden. The system consists of two parts: a dedicated outdoor air system (DOAS) to satisfy latent loads and ventilation requirements, and a water circuit to meet sensible heating and cooling loads. The novelty of the system is in relation to the water circuit, which is able to provide simultaneous heating and cooling through a single water loop that is near the room temperature. The energy performance of the system is currently being monitored through a number of sensors placed along the water circuit. Relevant physical parameters are being measured and data are available through a monitoring system. A preliminary analysis shows that the system is performing as designed. Results are shown for a typical week in winter, spring and summer. In particular, the supply water temperature in the circuit was between 20°C (in summer) and 23.2°C (in winter). The maximum supply/return temperature difference was found in summer and it assumed a value of 1.5 K. It is noticed that in spring supply and return water temperatures almost overlap.

COMPARISON OF COOLING AND HEATING REQUIREMENTS BETWEEN BRICK VENEER AND FIBRO CEMENT WALLING SYSTEM

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Swapan Saha ◽  
Dharma Hagare ◽  
Jiaqi Zhou ◽  
Md Kamrul Hassan
Keyword(s):  
Energy Consumption ◽  
Energy Cost ◽  
Energy Use ◽  
Net Present Value ◽  
Space Heating ◽  
Heating And Cooling ◽  
Space Cooling ◽  
Brick Veneer ◽  
Save Energy ◽  
Modern House

Space cooling and heating in residential sector is significant contributor to energy consumption in Australia. Therefore, it is important to reduce the cooling and heating requirements. The selection of a good walling system helps to save energy by homes. This research compared the thermal efficiency of a modern house (constructed using brick veneer walls with concrete floor slab) with an old house (constructed using fibro cement walls raised timber floor) using the AccuRate simulation tool. A standard house with two living rooms, one kitchen, one laundry and four bedrooms are simulated in a Sydney Suburb in Australia. It was found that modern house showed lower inside temperature variation than the old house all year around. The results also showed that the modern house has a lower energy consumption for space heating and cooling than the old house. The annual energy use for space heating and cooling in both the modern house and old house were 5197 kWh and 15,712 kWh respectively. Moreover, the annual energy costs were found to be $1,403 and $4,242 respectively for modern and old houses. The modern brick veneer house saved about 33 % of energy compared to old old house. When the net present value of the energy cost for f both houses over 50 years is computed, the energy cost of modern house was found to be $25,629 while it of old house is was $77,488 for the old house.

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