scholarly journals Techno-Economic Assessment of an Air-Multiple PCM Active Storage Unit for Free Cooling Application

2021 ◽  
Vol 13 (23) ◽  
pp. 12936
Author(s):  
Muriel Iten
Keyword(s):  
Energy Consumption ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Economic Assessment ◽  
Environmental Benefits ◽  
Office Building ◽  
Cooling Load ◽  
Storage Unit ◽  
Air Channels ◽  
Maintenance Requirements

A latent energy storage (LES) unit is presented in this paper for free space cooling and ventilation application. The unit includes multiple phase change materials (PCM) to advance the thermal performance of common LES units. It is composed by metallic rectangular panels containing commercial paraffins with melting temperatures ranging among 20 °C and 25 °C and surrounded by air channels. The average cooling load of the unit corresponds to approximately 1 kW over 8 h. It fulfils the peak ventilation cooling load during summer of an office building in Portugal. The study provides a techno-economic analysis and the environmental benefits of the LES technology compared to a traditional air conditioning (AC) unit for the cooling and ventilation of an office building. During daytime, the air-multiple PCM unit allows reducing the energy consumption by nearly 200 kWh. The full charging of the PMs during nighttime, requires significant energy consumption due to the high air flowrate demand for full solidification. The competitiveness of such units can be achieved by introducing fins into the panels, allowing double the energy savings. In an overall perspective, the unit presents several benefits such as lower initial cost and reduced maintenance requirements (non-use of refrigerants and batteries) that also allows better personal health issues when related to traditional ACs.

scholarly journals Improving Building Energy Performance Using Dual VAV Configuration Integrated with Dedicated Outdoor Air System

Buildings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 466
Author(s):  
Nabil Nassif ◽  
Iffat Ridwana
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
Energy Savings ◽  
Energy Performance ◽  
Office Building ◽  
Effective Control ◽  
Cooling Load ◽  
Outdoor Air ◽  
System A ◽  
Cooling Loads

As building systems account for almost half of the total energy consumed by the building sector to provide space heating, cooling, and ventilation, efficiently designing these systems can be the key to energy conservation in buildings. Dual VAV systems with an effective control strategy can substantially reduce the energy consumption in buildings, providing a significant scope of further research on this system configuration. This paper proposes to utilize the warm air duct of the dual VAV system as a dedicated outdoor air (DOA) unit when no heating is required, which allows the cooling load to be effectively distributed between two ducts. A specific control sequence is proposed with different supply air temperature reset strategies to estimate the heating, cooling loads, and fan power energy consumption of the proposed system. A simple two-zone office building is taken as a preliminary case study to simulate the airflow rates and fan power of a single duct VAV and proposed dual VAV systems to illustrate the concept. Finally, a larger multi-zone office building is simulated to measure the annual heating, cooling loads, and fan power energy and compare the energy savings among the systems. The results show significant fan power reduction ranging from 1.7 to 9% and notable heating energy reduction up to 76.5% with a small amount of cooling load reduction varying from 0.76 to 2.56% depending on the different locations for the proposed dual VAV systems. Further energy savings from different supply air temperature reset strategies demonstrate the opportunity of employing them according to climates and case studies. The proposed dual VAV system proves to have the potential to be adapted in buildings for the purpose of sustainability and energy savings.

Experimental Study of PCM Inclusion in Different Building Envelopes

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
C. Castellón ◽  
A. Castell ◽  
M. Medrano ◽  
I. Martorell ◽  
L. F. Cabeza
Keyword(s):  
Energy Consumption ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Construction Materials ◽  
Temperature Oscillation ◽  
Heat Pumps ◽  
Hvac System ◽  
Small House ◽  
Trombe Wall ◽  
Insulation Effect

The main objective of this paper is to demonstrate experimentally that it is possible to improve the thermal comfort and reduce the energy consumption of a building without substantial increase in the weight of the construction materials with the inclusion of phase change materials (PCM). PCM are a suitable and promising technology for this application. This paper presents an experimental setup to test PCM with various typical insulation and construction materials in real conditions in Puigverd de Lleida (Lleida, Spain). Nine small house-sized cubicles were constructed: two with concrete, five with conventional brick, and two with alveolar brick. PCM was added in one cubicle of each typology. For each type of construction specific experiments were done. In all cubicles, free-floating temperature experiments were performed to determine the benefits of using PCM. A Trombe wall was added in both concrete cubicles and its influence was investigated. All brick cubicles were equipped with domestic heat pumps as Heating, Ventilation, and Air Conditioning (HVAC) system; therefore, the energy consumption was registered, providing real information about the energy savings. Results were very good for the concrete cubicles, since temperature oscillation were reduced by up to 4°C through the use of PCM and also peak temperatures in the PCM cubicle were shifted in later hours. In the brick cubicles, the energy consumption of the HVAC system in summer was reduced by using PCM for set points higher than 20°C. During winter an insulation effect of the PCM is observed, keeping the temperatures of the cubicles warmer, especially during the cold hours of the day.

scholarly journals Heating and cooling requirement of an office building and urban rooftop greenhouse

2021 ◽  
Author(s):  
Andrea Vickers
Keyword(s):  
Food Security ◽  
Energy Consumption ◽  
Urban Agriculture ◽  
Energy Savings ◽  
Simulation Software ◽  
Office Building ◽  
Thermal Mass ◽  
Heating And Cooling ◽  
Several Variables ◽  
Potential Impact

Urban agriculture is an important step towards food security in cities where rooftop space is abundant, and underused. This research addresses the potential impact of adding a rooftop greenhouse to a six storey, detached office building on the total heating and cooling energy consumption of both structures operated year‐round, using IES‐VE simulation software. Several variables including the level of insulation between the office building and greenhouse, additional thermal mass, the greenhouse envelope and greenhouse internal loads were tested to observe trends that suggest an impact on the system’s conditioning energy due to the presence of the greenhouse. Overall, it was found to be most likely that the greatest energy savings for an integrated office building and rooftop greenhouse would be achieved with the highest resistance greenhouse envelope possible, which may be limited by the light needs of plants grown in the greenhouse, and incorporation of thermal mass in the greenhouse.

Heating System Supervisory Control for Residential Energy Conservation

2009 ◽  
Author(s):  
D’Angelo R. Woods ◽  
James S. Hammonds
Keyword(s):  
Energy Consumption ◽  
Supervisory Control ◽  
Energy Savings ◽  
Heating System ◽  
Hot Water ◽  
System Control ◽  
Thermal Source ◽  
Storage Unit ◽  
Control Approach ◽  
Energy Storage Unit

For most households space heating and domestic hot water production constitute the largest portion of energy consumption, which for a typical home space and water heating can comprise over 60% of the total energy usage. Therefore significant energy savings can be accomplished by using energy sources and systems for heating more efficiently. An approach discussed in this work uses system controls to better manage available resources and balance user comfort with efficient use of energy systems. In this work the results of a supervisory control approach applied to residential heating system are presented. The control system is characterized by a supervisory unit that controls the subsystems. The subsystems of this analysis include a thermal source and an energy storage unit. Dynamic thermal system control is demonstrated using a real-time, pseudo-hardware-in-the-loop test bench. The results show the potential reduction of energy consumption through advanced control implementation.

scholarly journals Alternativa energética sustentable mediante la utilización de aislantes térmicos de diferentes materiales en edificaciones con sistemas de aire acondicionado

2020 ◽  
pp. 1-8
Author(s):  
Edzel Jair Casados-López ◽  
Alvaro Casados-Sánchez ◽  
Raúl Cruz-Vicencio ◽  
Alvaro Horst-Sánche
Keyword(s):  
Energy Consumption ◽  
Air Conditioning ◽  
Energy Savings ◽  
Cooling Load ◽  
Test Models ◽  
Scale Models ◽  
Conditioning Equipment ◽  
Actual Energy Consumption ◽  
Reduction Of Co2 ◽  
The City

A methodology is proposed for calculating the cooling load and the energy consumption of air conditioning equipment in three scale models of buildings under study, using the ASHRAE CLTD / SCL / CLF method. The building in which the mentioned method is used are three scale models of buildings located in the city of Poza Rica, state of Veracruz, Mexico. This method is applied in order to obtain the cooling load as exact as possible and thus avoid oversizing in air conditioning equipment, and by using thermal insulation, achieve a decrease in energy consumption and thus contribute to the reduction of CO2 emissions, to energy saving and therefore to sustainable development. The cooling load is calculated by applying the proposed methodology to three cases: model A, B and C. The results for the three test models, object of this study, are compared. Measurements of energy consumption are made to perform the error analysis of the actual energy consumption with respect to that calculated using the method. Finally, energy savings are quantified, in the cases mentioned.

scholarly journals Retrofitting an Existing Office Building in the UAE Towards Achieving Low-Energy Building

2020 ◽  
Vol 12 (6) ◽  
pp. 2573
Author(s):  
Maatouk Khoukhi ◽  
Abeer Fuad Darsaleh ◽  
Sara Ali
Keyword(s):  
Energy Consumption ◽  
Lower Energy ◽  
Energy Savings ◽  
Building Design ◽  
Office Building ◽  
Design Parameters ◽  
Base Case ◽  
Hvac System ◽  
Existing Buildings ◽  
Existing Building

Retrofitting an existing building can oftentimes be more cost-effective than building a new facility. Since buildings consume a significant amount of energy, particularly for heating and cooling, and because existing buildings comprise the largest segment of the built environment, it is important to initiate energy conservation retrofits to reduce energy consumption and the cost of heating, cooling, and lighting buildings. However, conserving energy is not the only reason for retrofitting existing buildings. The goal should be to create a high-performance building by applying an integrated, whole-building design process to the project during the planning phase that ensures that all key design objectives are met. This paper presents a real case study of the retrofitting of an existing building to achieve lower energy consumption. Indeed, most of the constructed buildings in the UAE are unsuitable for the region, which is characterized by a very harsh climate that causes massive cooling loads and energy consumption due to an appropriate selection of design parameters at the design level. In this study, a monthly computer simulation of energy consumption of an office building in Sharjah was carried out under UAE weather conditions. Several parameters, including the building orientation, heating, ventilation, and air conditioning (HVAC) system, external shading, window-to-wall ratio, and the U-values of the walls and the roof, were investigated and optimized to achieve lower energy consumption. The simulation shows that the best case is 41.7% more efficient than the real (original) case and 30.6% more than the base case. The most sensitive parameter in the retrofitting alternatives is the roof component, which affects the energy savings by 8.49%, followed by the AC system with 8.34% energy savings if well selected using the base case. Among the selected five components, a new roof structure contributed the most to the decrease in the overall energy consumption (approximately 38%). This is followed by a new HVAC system, which leads to a 37% decrease, followed by a new wall type with insulation, resulting in a 20% decrease.

scholarly journals Research on the Comprehensive Performance of Hygroscopic Materials in an Office Building Based on EnergyPlus

Energies ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 191 ◽  
Author(s):  
Shui Yu ◽  
Yumeng Cui ◽  
Yifei Shao ◽  
Fuhong Han
Keyword(s):  
Energy Consumption ◽  
Moisture Content ◽  
Life Cycle Cost ◽  
Energy Savings ◽  
Initial Moisture Content ◽  
Office Building ◽  
Weak Links ◽  
Energy Consumption Analysis ◽  
Passive Materials ◽  
Moisture Buffering

This paper presents the research status of hygroscopic materials, points out the weak links as targets for major breakthroughs, and introduces humidifying mechanisms and their categories. In this paper, we simulated a single-monomer Shenyang office building with different envelopes of inner-surface hygroscopic materials for indoor humidity conditions, energy consumption, and economy, which are three aspects of energy consumption analysis in EnergyPlus software. To obtain the best moisture buffering performance from hygroscopic materials, we also simulated different cases including the laying area, ventilation strategy, thickness, and initial moisture content of different hygroscopic materials. The humidity fluctuation, with changes in the style of hygroscopic materials and usage conditions, of a room in a building can be analyzed by numerical simulation. This allows the determination of the best moisture buffering performance of the building structure. The results show that hygroscopic materials have great advantages in three energy saving aspects of building assessment. Hygroscopic materials can regulate indoor air humidity and reduce energy consumption. In addition, the entire life-cycle cost can be minimized. Lower rates of air exchange and larger usable areas can help enhance the level of performance of hygroscopic materials. The thickness and initial moisture content of hygroscopic materials have little impact on the moisture buffering value. This study strived to provide a theoretical basis and technical guidance for the production and installation of hygroscopic materials. It also promoted the passive materials market and the building’s energy savings. The best moisture buffering performance, evaluated at room level in this paper, can be obtained through real-world environmental simulation.

scholarly journals Improving Comfort and Air Conditioner Performance by Optimizing Controllers under Actual Usage Conditions

2021 ◽  
Vol 11 (11) ◽  
pp. 4818
Author(s):  
Taebyoung Park ◽  
Byungsoon Kim ◽  
Gilun Hwang ◽  
Yulho Kang ◽  
Inwon Lee ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Savings ◽  
Control Method ◽  
Pressure Control ◽  
Load Estimation ◽  
Cooling Load ◽  
Air Conditioner ◽  
Actual Usage ◽  
Target Pressure ◽  
The Difference

This study is to increase the efficiency of the air conditioning system under actual conditions of use. In order to improve the increase in energy consumption due to control without considering indoor cooling load fluctuations, we review it compared to conventional control methods in two respects. First, we examined the control method to reduce energy consumption by varying the evaporative pressure of the system according to the cooling load, and secondly, further reducing energy consumption by controlling the revolutions per minute (RPM) of the fan of the indoor unit at the same time as the pressure fluctuation under the cooling load. We found that changing the target pressure depending on the difference between the target temperature and room temperature can control temperature more efficiently and save energy than using fixed target pressure, and that the effect increases when applying the control of the air volume of the indoor air. Cleaning up the resulting values, the fan-load-control condition of the cooling-load-estimation control method showed an energy savings effect of 16.1%–48.7% compared with the fixed-pressure control method and 1.2%–37.7% compared with the cooling-load-estimation control method.

scholarly journals Reducing The Energy Consumption By Using Floor Heating With Phase Change Materials In The Toronto Climate

2021 ◽  
Author(s):  
Lindsay Fialkov
Keyword(s):  
Energy Consumption ◽  
Phase Change ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Cost Savings ◽  
Heating System ◽  
Radiant Floor Heating System ◽  
The Cost ◽  
The Impact ◽  
Floor Heating

This major research project focuses on reducing the energy consumption, by modelling a radiant floor heating system with phase change materials, in the Toronto climate. Computer generated simulations were performed using DesignBuilder software, using an example of a typical condominium in Toronto .Two south facing suites and two north facing suites were investigated. Of those suites, one north facing suite had PCM below the finished floor, as well as one south facing suite. The objective of these simulations was to determine the impact of using PCM in the condo suites. Three different types of PCM were used, in order to determine which type had the biggest energy savings. The PCMs were M91/Q21, M51/Q21 and M27/Q21. The final results showed that the suites with the M27/Q21 PCM had the lowest energy usage. A cost savings comparison was performed based on the rate of energy used and the cost of the energy, provided by the Ontario Energy Board.

Investigation of Thermal and Energy Performance of Green Roofs in Florida Climate

2017 ◽  
Author(s):  
Dhruv Sangal ◽  
Hamidreza Najafi
Keyword(s):  
Mathematical Model ◽  
Energy Consumption ◽  
Energy Savings ◽  
Green Roofs ◽  
Building Energy ◽  
The United States ◽  
Energy Performance ◽  
Environmental Benefits ◽  
Energy Usage ◽  
Heating Load

Buildings are responsible for approximately 40% of energy consumption in the United States. Utilizing efficient methods for reduction in energy consumption by buildings is of great importance. Green roofs have been known as an effective approach to reduce building energy usage (associated with cooling and heating load) as well as providing environmental benefits. In the present paper, a mathematical model is developed in MATLAB considering several aspects of green roofs. The model is validated using available data from previous experimental research studies. A simulation is conducted to assess the performance of green roofs in Melbourne, FL. The study includes calculation of the energy savings associated with using a green roof in summer months and winter months.

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