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.

scholarly journals Energy Conservation Potential of Economizer Controls Using Optimal Outdoor Air Fraction Based on Field Study

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5038
Author(s):  
Goopyo Hong ◽  
Chul Kim ◽  
Jun Hong
Keyword(s):  
Energy Consumption ◽  
Energy Conservation ◽  
Temperature Control ◽  
Energy Savings ◽  
Cooling System ◽  
Energy Performance ◽  
Outdoor Air ◽  
Humid Climate ◽  
Differential Enthalpy ◽  
The Impact

In commercial buildings, HVAC systems are becoming a primary driver of energy consumption, which already account for 45% of the total building energy consumption. In the previous literature, researchers have studied several energy conservation measures to reduce HVAC system energy consumption. One of the effective ways is an economizer in air-handling units. Therefore, this study quantified the impact of the outdoor air fraction by economizer control type in cooling system loads based on actual air-handling unit operation data in a hospital. The optimal outdoor air fraction and energy performance for economizer control types were calculated and analyzed. The result showed that economizer controls using optimal outdoor air fraction were up to 45% more efficient in cooling loads than existing HVAC operations in the hospital. The energy savings potential was 6–14% of the differential dry-bulb temperature control, 17–27% of the differential enthalpy control, 8–17% of the differential dry-bulb temperature and high-limit differential enthalpy control, and 16–27% of the differential enthalpy and high-limit differential dry-bulb temperature control compared to the no economizer control. The result of this study will contribute to providing a better understanding of economizer controls in the hospital when the building operates in hot-humid climate regions.

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.

Comparison of static and dynamic shading systems for office building energy consumption and cooling load assessment

2018 ◽  
Vol 29 (5) ◽  
pp. 978-998 ◽  
Author(s):  
Francesco De Luca ◽  
Hendrik Voll ◽  
Martin Thalfeldt
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Control Algorithm ◽  
Office Buildings ◽  
Office Building ◽  
Cooling Load ◽  
Content Type ◽  
Improve Energy Efficiency ◽  
Shading Devices ◽  
Cooling Loads

PurposeExterior shading devices and dynamic shading systems constitute an efficient way to improve energy efficiency and occupants’ comfort in buildings through the reduction of direct solar heat gains and disturbing glare. The purpose of this paper is to analyse the performance of different types of shading systems, fixed and dynamic, and their influence on the energy consumption and cooling loads for an office building located in Tallinn, Estonia. The scope is to determine the most performative configuration for energy consumption and cooling load reduction for office buildings and to provide designers and developers with the necessary knowledge to increase the performance of their buildings.Design/methodology/approachThere are many types of fixed shading devices, most of which use rectangular planar elements, the orientation and layout of which depends on the building location and façade orientation. The dynamic shading systems vary on the base of the building occupancy schedules and occupants’ preferences. The paper presents a method to determine the most efficient type and size of fixed shading devices in relation to different windows’ size and orientation, and the quantity of windows panes. At the same time the dynamic shading system using a control algorithm developed by the authors is compared.FindingsThe results show that solar shading is an efficient way to control the energy consumption of office buildings, though with different efficacy by the static systems depending on orientation, window and shading type. Evidence shows that dynamic blind systems have more uniform performance and usually outperform static shading.Originality/valueThe paper compares the performances of different static and dynamic shading devices and systems for the location in Tallinn. The dynamic shading system tested uses a control algorithm developed by the authors. The indications for the energy reduction and cooling loads are a valuable resource for designers and developers to increase the energy efficiency of their buildings.

scholarly journals Selected Aspects of Indoor Climate in a Passive Office Building with a Thermally Activated Building System: A Case Study from Poland

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 860
Author(s):  
Piotr Michalak
Keyword(s):  
Air Temperature ◽  
Thermal Conditions ◽  
Office Building ◽  
Normal Operation ◽  
Indoor Climate ◽  
Thermally Activated ◽  
System A ◽  
Warm Sensation ◽  
Building System ◽  
Heating Energy Consumption

Modern buildings with new heating, ventilation and air conditioning (HVAC) systems offer possibility to fit parameters of the indoor environment to the occupants’ requirements. The present paper describes the results of measurements performed in an office room in the first Polish passive commercial office building during four months of normal operation. They were used to calculate parameters describing thermal comfort: vertical air temperature profile, floor surface temperature, predicted mean vote (PMV) and predicted percent of dissatisfied (PPD). Obtained results confirmed good thermal conditions in the analysed room. The average temperature of the floor’s surface varied from 20.6 °C to 26.2 °C. The average vertical air temperature, calculated for working days, was from 22.5 °C to 23.1 °C. The temperature difference between the floor and 5 cm below the ceiling was from −0.9 °C to 6.3 °C. The PMV index varied from 0.52 to 1.50 indicating ‘slightly warm’ sensation, in spite of ‘neutral’ reported by employees. Also measured cooling and heating energy consumption was presented. The performed measurements confirmed the ability of thermally activated building system (TABS) to keep good thermal conditions.

scholarly journals Towards Sustainable Energy Retrofitting, a Simulation for Potential Energy Use Reduction in Residential Buildings in Palestine

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3876
Author(s):  
Sameh Monna ◽  
Adel Juaidi ◽  
Ramez Abdallah ◽  
Aiman Albatayneh ◽  
Patrick Dutournie ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Use ◽  
Energy Savings ◽  
Residential Buildings ◽  
Residential Building ◽  
Simulation Models ◽  
Water Heating ◽  
Heating And Cooling ◽  
Space Cooling ◽  
Cooling Loads

Since buildings are one of the major contributors to global warming, efforts should be intensified to make them more energy-efficient, particularly existing buildings. This research intends to analyze the energy savings from a suggested retrofitting program using energy simulation for typical existing residential buildings. For the assessment of the energy retrofitting program using computer simulation, the most commonly utilized residential building types were selected. The energy consumption of those selected residential buildings was assessed, and a baseline for evaluating energy retrofitting was established. Three levels of retrofitting programs were implemented. These levels were ordered by cost, with the first level being the least costly and the third level is the most expensive. The simulation models were created for two different types of buildings in three different climatic zones in Palestine. The findings suggest that water heating, space heating, space cooling, and electric lighting are the highest energy consumers in ordinary houses. Level one measures resulted in a 19–24 percent decrease in energy consumption due to reduced heating and cooling loads. The use of a combination of levels one and two resulted in a decrease of energy consumption for heating, cooling, and lighting by 50–57%. The use of the three levels resulted in a decrease of 71–80% in total energy usage for heating, cooling, lighting, water heating, and air conditioning.

scholarly journals Basic Passive Side-Day lighting Considerations for High Rise office Building

2020 ◽  
Vol 9 (5) ◽  
pp. 78-87
Keyword(s):  
Energy Consumption ◽  
Construction Industry ◽  
Positive Impact ◽  
Building Design ◽  
High Energy ◽  
Office Building ◽  
High Rise ◽  
Design Considerations ◽  
System A ◽  
Modern Era

High rise office building design is one of the essential buildings in construction industry due to the limited space especially in the urban area. After home, a high rise office building is an important space for human in modern era. Due to the issue of high energy consumption especially inefficient artificial light strategy, side-day lighting becomes the best solution for a high rise office building design. Despite providing efficient energy consumption, side-day lighting creates a positive impact to the worker as well as the office's indoor environment. Hence, this paper aims to explore the basic passive side-day lighting considerations that educate people especially for those who are involved in the building construction industry. Beside, this paper focuses on the passive design considerations due to the various advantages that not involved especially with complex electrical and mechanical system. A systematic literature review is the main methodology for this paper to identify the basic passive side-day lighting considerations for a high rise office building design. Base on this research, it revealed that eight elements for building design considerations should be applied to provide a better day lighting impact for a high rise office building design. Considerations for non-building design aspects should also need to be applied since those aspects contribute to produce a better day lighting impact for a high rise office building design.

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.

scholarly journals Transformation of an Office Building into a Nearly Zero Energy Building (nZEB): Implications for Thermal and Visual Comfort and Energy Performance

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 895 ◽  
Author(s):  
Ilaria Ballarini ◽  
Giovanna De Luca ◽  
Argun Paragamyan ◽  
Anna Pellegrino ◽  
Vincenzo Corrado
Keyword(s):  
Thermal Comfort ◽  
Energy Savings ◽  
Energy Performance ◽  
Primary Energy ◽  
Building Envelope ◽  
Office Building ◽  
Indoor Environmental Quality ◽  
Visual Comfort ◽  
Zero Energy ◽  
Efficiency Measures

Directive 2010/31/EU promotes the refurbishment of existing buildings to change them into nearly zero-energy buildings (nZEBs). Within this framework, it is of crucial importance to guarantee the best trade-off between energy performance and indoor environmental quality (IEQ). The implications of a global refurbishment scenario on thermal and visual comfort are assessed in this paper pertaining to an existing office building. The retrofit actions applied to achieve the nZEB target consist of a combination of envelope and technical building systems refurbishment measures, involving both HVAC and lighting. Energy and comfort calculations were carried out through dynamic simulation using Energy Plus and DIVA, for the thermal and visual performance assessments, respectively. The results point out that energy retrofit actions on the building envelope would lead to significant improvements in the thermal performance, regarding both energy savings (−37% of the annual primary energy for heating) and thermal comfort. However, a daylighting reduction would occur with a consequent higher electricity demand for lighting (36%). The research presents a detailed approach applicable to further analyses aimed at optimizing the energy efficiency measures in order to reduce the imbalance between visual and thermal comfort and to ensure the best performance in both domains.

scholarly journals Comparative thermal performance of static sunshade and brick cavity wall for energy efficient building envelope in composite climate

2014 ◽  
Vol 18 (3) ◽  
pp. 925-934 ◽  
Author(s):  
Meghana Charde ◽  
Sourabh Bhati ◽  
Ayushman Kheterpal ◽  
Rajiv Gupta
Keyword(s):  
Energy Consumption ◽  
Air Temperature ◽  
Indoor Air ◽  
Energy Efficient ◽  
Building Envelope ◽  
Combined Effect ◽  
Cavity Wall ◽  
Outdoor Air ◽  
Reduce Energy Consumption ◽  
Energy Efficient Building

Energy efficient building technologies can reduce energy consumption in buildings. In present paper effect of designed static sunshade, brick cavity wall with brick projections and their combined effect on indoor air temperature has been analyzed by constructing three test rooms each of habitable dimensions (3.0 m ? 4.0 m ? 3.0 m) and studying hourly temperatures on typical days for one month in summer and winter each. The three rooms have also been simulated using a software and the results have been compared with the experimental results. Designed static sunshade increased indoor air temperature in winter while proposed brick cavity wall with brick projections lowered it in summer. Combined effect of building elements lowered indoor air temperature in summer and increased it in winter as compared to outdoor air temperature. It is thus useful for energy conservation in buildings in composite climate.

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