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.

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.

scholarly journals Reduction of Energy Intensity in Broiler Facilities: Methodology and Strategies

2021 ◽  
Vol 8 ◽  
Author(s):  
Catherine Baxevanou ◽  
Dimitrios Fidaros ◽  
Ilias Giannenas ◽  
Eleftherios Bonos ◽  
Ioannis Skoufos
Keyword(s):  
Energy Consumption ◽  
Energy Saving ◽  
Thermal Energy ◽  
Energy Intensity ◽  
Electrical Energy ◽  
Energy Performance ◽  
Advanced Technology ◽  
Energy Audit ◽  
Wind Potential ◽  
Technology Level

Broiler facilities consume a lot of energy resulting in natural source depletion and greater greenhouse gas emissions. A way to assess the energy performance of a broiler facility is through an energy audit. In the present paper, an energy protocol for an energy audit is presented covering both phases of data collection and data elaboration. The operational rating phase is analytically and extendedly described while a complete mathematical model is proposed for the asset rating phase. The developed energy audit procedure was applied to poultry chambers located in lowland and mountainous areas of Epirus Greece for chambers of various sizes and technology levels. The energy intensity indices varied from 46 to 89 kWh/m2 of chamber area 0.25–0.48 kWh/kg of produced meat or 0.36–1.3 kWh/bird depending on the chamber technology level (insulation, automation, etc.) and the location where the unit was installed. The biggest energy consumer was heating followed by energy consumption for ventilation and cooling. An advanced technology level can improve energy performance by ~ 27%−31%. Proper insulation (4–7 cm) can offer a reduction of thermal energy consumption between 10 and 35%. In adequately insulated chambers, the basic heat losses are due to ventilation. Further energy savings can be achieved with more precise ventilation control. Automation can offer additional electrical energy saving for cooling and ventilation (15–20%). Energy-efficient lights can offer energy saving up to 5%. The use of photovoltaic (PV) technology is suggested mainly in areas where net-metering holds. The use of wind turbines is feasible only when adequate wind potential is available. Solar thermal energy is recommended in combination with a heat pump if the unit's heating and cooling systems use hot/cold water or air. Finally, the local production of biogas with anaerobic fermentation for producing thermal or electrical energy, or cogenerating both, is a choice that should be studied individually for each farm.

scholarly journals Identification of Energy Efficiency Improvement Measures of an Existing Residential Building Using Audit-Assisted Energy Simulation and Analysis

2021 ◽  
Vol 12 (1) ◽  
pp. 18
Author(s):  
Farrukh Arif ◽  
Rabia Khalid ◽  
Nida Azhar
Keyword(s):  
Energy Cost ◽  
Energy Efficient ◽  
Natural Ventilation ◽  
Residential Buildings ◽  
Residential Building ◽  
Energy Performance ◽  
Information Modeling ◽  
Energy Efficiency Improvement ◽  
Improvement Measures ◽  
Potential Improvement

Depleting energy sources are forcing humans to preserve energy and utilize it wisely. Globally, researchers are working to find ways to manage the energy crisis. Residential buildings are considered to be in the most energy demanding sector. Therefore, efforts are being made to reduce the increasing energy consumption and make the buildings energy efficient. The paper focuses on finding ways to retrofit the existing residential buildings into energy efficient buildings. This study evaluated the energy performance of a G+2 residential building with a total of 3 floors covering an area of 991.68 sq. meters, to identify relevant potential improvement measures. An energy analysis of the building was performed using information modeling assisted with energy audit data for accurate and realistic analysis. It was found that there is potential for the reduction of the annual energy usage and annual energy cost up to 2.33% and 4.54% respectively, by making improvements in the window to wall ratio. Another potential energy cost saving of 14.8% can be achieved by changing Heating, Ventilation, Air Conditioning (HVAC) type, and 7.62% of a reduction in cost can be achieved through modification in lighting fixtures. Moreover, installing solar photovoltaic panels can save up to PKR 1 million, and natural ventilation could result in saving more than PKR 0.2 million annually.

scholarly journals Green Roofs as Effective Tools for Improving the Indoor Comfort Levels of Buildings—An Application to a Case Study in Sicily

2020 ◽  
Vol 10 (3) ◽  
pp. 893 ◽  
Author(s):  
Laura Cirrincione ◽  
Maria La Gennusa ◽  
Giorgia Peri ◽  
Gianfranco Rizzo ◽  
Gianluca Scaccianoce ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Demand ◽  
Electric Energy ◽  
Simulation Models ◽  
Green Roofs ◽  
Energy Performance ◽  
Comfort Levels ◽  
Indoor Comfort ◽  
The Impact

In the line of pursuing better energy efficiency in human activities that would result in a more sustainable utilization of resources, the building sector plays a relevant role, being responsible for almost 40% of both energy consumption and the release of pollutant substances in the atmosphere. For this purpose, techniques aimed at improving the energy performances of buildings’ envelopes are of paramount importance. Among them, green roofs are becoming increasingly popular due to their capability of reducing the (electric) energy needs for (summer) climatization of buildings, hence also positively affecting the indoor comfort levels for the occupants. Clearly, reliable tools for the modelling of these envelope components are needed, requiring the availability of suitable field data. Starting with the results of a case study designed to estimate how the adoption of green roofs on a Sicilian building could positively affect its energy performance, this paper shows the impact of this technology on indoor comfort and energy consumption, as well as on the reduction of direct and indirect CO2 emissions related to the climatization of the building. Specifically, the ceiling surface temperatures of some rooms located underneath six different types of green roofs were monitored. Subsequently, the obtained data were used as input for one of the most widely used simulation models, i.e., EnergyPlus, to evaluate the indoor comfort levels and the achievable energy demand savings of the building involved. From these field analyses, green roofs were shown to contribute to the mitigation of the indoor air temperatures, thus producing an improvement of the comfort conditions, especially in summer conditions, despite some worsening during transition periods seeming to arise.

Application of Fatty Acid Based Phase-Change Material to Reduce Energy Consumption From Roofs of Buildings

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Ahmad K. Sleiti ◽  
Edward J. Naimaster
Keyword(s):  
Fatty Acid ◽  
Energy Consumption ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Energy Performance ◽  
Department Of Energy ◽  
Total Energy Consumption ◽  
Scanning Calorimetry ◽  
Change Material

Buildings account for a significant portion of the total energy consumption in the U.S., especially the energy-inefficient commercial building sector. As part of the future path toward realizing net zero energy buildings, innovative energy-efficient technologies must be developed. In this study, the potential of phase-change material (PCM)-enhanced constructions to lower heating, ventilating, and air conditioning (HVAC) energy consumption in a commercial restaurant building was investigated. A commercially available fatty acid based PCM product was selected due to their promising thermal and chemical properties. Differential scanning calorimetry (DSC) was used in isothermal step mode to accurately measure the latent heat energy storage of the PCM. A U.S. Department of Energy (DOE) commercial reference building model with a PCM-enhanced ceiling was simulated using a finite-difference conduction heat transfer algorithm in EnergyPlus to determine the effects of the PCM on the building energy performance. It was found that, although the PCM-enhanced ceiling had a beneficial stabilizing effect on the interior surface temperature of the ceiling, the zone mean air temperatures were not significantly altered. As such, minimal HVAC energy savings were seen. Future work should focus on active PCM systems, which utilize heat exchanging fluids to discharge the PCM to remove the stored thermal energy of the PCM during the night in summer, overcoming the fundamental issue of the passive PCM system returning stored thermal energy back into the building.

scholarly journals Energy and Climate Analysis of Greenhouse System for Tomatoes Cultivation using CFD and Open Studio Energy Plus Software

2018 ◽  
Vol 7 (3.11) ◽  
pp. 183
Author(s):  
N Y Dahlan ◽  
Ahmad Amiruddin ◽  
Nguyen Duc Luong ◽  
Siti Zaharah Sakimin
Keyword(s):  
Energy Consumption ◽  
Relative Humidity ◽  
Indoor Environment ◽  
Climate Changes ◽  
Electrical Equipment ◽  
Energy Performance ◽  
Tomato Plants ◽  
Energy Plus ◽  
Computational Fluid Dynamics Cfd ◽  
Climate Analysis

Tomato plants are sensitive toward climate changes thus affecting growth development and pollination of the plant. This study was conducted to assess energy performance and environment in greenhouse agriculture to support tomatoes cultivation using Computational Fluid Dynamics (CFD) and OpenStudio EnergyPlus software. To achieve efficient energy performance and to balance it with the environment in tomato greenhouse, architectural and engineering design have been integrated in the study. Analyses on indoor environment and energy consumption of the greenhouse are carried out by installing various electrical equipment such as exhaust fans and humidifier in the greenhouse to meet indoor environment requirement of good tomato cultivation. Three properties of the greenhouse were monitored and these are temperature, relative humidity and energy consumption. Results show that the proposed greenhouse model in this study could meet the required temperature and relative humidity for good tomatoes cultivation. 

scholarly journals Data-Driven Virtual Replication of Thermostatically Controlled Domestic Heating Systems

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5430
Author(s):  
Gerard Mor ◽  
Jordi Cipriano ◽  
Eloi Gabaldon ◽  
Benedetto Grillone ◽  
Mariano Tur ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Savings ◽  
Energy Performance ◽  
Hot Water ◽  
Data Driven ◽  
Space Heating ◽  
Climate Data ◽  
Automatic Assessment ◽  
Point Temperature ◽  
Set Point

Thermostatic load control systems are widespread in many countries. Since they provide heat for domestic hot water and space heating on a massive scale in the residential sector, the assessment of their energy performance and the effect of different control strategies requires simplified modeling techniques demanding a small number of inputs and low computational resources. Data-driven techniques are envisaged as one of the best options to meet these constraints. This paper presents a novel methodology consisting of the combination of an optimization algorithm, two auto-regressive models and a control loop algorithm able to virtually replicate the control of thermostatically driven systems. This combined strategy includes all the thermostatically controlled modes governed by the set point temperature and enables automatic assessment of the energy consumption impact of multiple scenarios. The required inputs are limited to available historical readings from smart thermostats and external climate data sources. The methodology has been trained and validated with data sets coming from a selection of 11 smart thermostats, connected to gas boilers, placed in several households located in north-eastern Spain. Important conclusions of the research are that these techniques can estimate the temperature decay of households when the space heating is off as well as the energy consumption needed to reach the comfort conditions. The results of the research also show that estimated median energy savings of 18.1% and 36.5% can be achieved if the usual set point temperature schedule is lowered by 1 °C and 2 °C, respectively.

scholarly journals The Role and Place of Traditional Chimney System Solutions in Environmental Progress and in Reducing Energy Consumption

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4720
Author(s):  
Dariusz Bajno ◽  
Łukasz Bednarz ◽  
Agnieszka Grzybowska
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Fossil Fuels ◽  
Global Climate ◽  
Current Trend ◽  
Simulation Models ◽  
Energy Performance ◽  
Heat Losses ◽  
Building Structures ◽  
Wide Range

Buildings, energy, and the environment are key issues facing construction around the world. The energy efficiency of buildings is a key topic when it comes to reducing the world’s energy consumption, releasing harmful gases, and global climate change, as they consume about 40% of the world’s energy supplies. Heat losses in buildings reduce the energy performance of buildings and are basically important to them. In the paper, the authors focus on the main problems related to heat losses generated by chimney systems, which are inseparable equipment of building structures, resulting in lower energy efficiency and, at the same time, technical efficiency and durability of the building partitions themselves. Authors present thermal imaging with its contribution to the detection of heat losses, thermal bridges, insulation problems, and other performance disturbances, and then verifications using appropriate simulation models. The mathematical apparatus of artificial neural networks was implemented to predict the temperature distributions on the surfaces of prefabricated chimney solutions. In Europe, we can often find a large building substance equipped with traditional chimneys, which disrupts the current trend of striving to reduce energy consumption, especially that derived from fossil fuels. Speaking of energy-efficient buildings, one should not ignore those that, without additional security and modern installations, are constantly used in a very wide range. Therefore, the article deals with an essential problem that is not perceived in design studies and during the operation period as having a basis in incorrect architectural solutions and which can be easily eliminated. It concerns the cooling of internal partitions of buildings on their last storeys, in places where chimneys are located, regardless of their function. The authors of the paper decided to take a closer look at this phenomenon, which may allow the limiting of its effects and at the same time reduce its impact on the energy performance of technologically older buildings.

scholarly journals Analytical Model for Compressed Air System Analysis

2021 ◽  
pp. 99-104
Author(s):  
Mohamad Thabet ◽  
David Sanders ◽  
Victor Becerra
Keyword(s):  
Energy Consumption ◽  
Analytical Model ◽  
Storage Tank ◽  
System Analysis ◽  
Energy Performance ◽  
Compressed Air ◽  
Supply Side ◽  
Set Point ◽  
System Pressure ◽  
Air System

AbstractThis paper presents a simple analytical model for a compressed air system (CAS) supply side. The supply side contains components responsible for production, treatment and storage of compressed air such as a compressor, cooler and a storage tank. Simulation of system performance with different storage tank size and system pressure set-point were performed. Results showed that a properly sized tank volume reduces energy consumption while maintaining good system pressure stability. Moreover, results also showed that reducing system pressure reduced energy consumption, however a more detailed model that considers end-user equipment is required to study effect of pressure set-point on energy consumption. Future work will focus on developing a supply-demand side coupled model and on utilizing model in developing new control strategies for improved energy performance.

Sign in / Sign up

Export Citation Format

Share Document