Thermal and flow resistance characteristics of a parallel-pipe type natural heat transfer air-conditioning terminal device for nearly zero energy buildings

2020 ◽  
Vol 29 (9) ◽  
pp. 1227-1237
Author(s):  
Haiwen Shu ◽  
Hongbin Wang ◽  
Guangyu Cao
Keyword(s):  
Heat Transfer ◽  
Air Conditioning ◽  
Flow Resistance ◽  
Thermal Environment ◽  
Engineering Application ◽  
Zero Energy ◽  
Terminal Device ◽  
Operation Conditions ◽  
Heating And Cooling ◽  
Zero Energy Building

A nearly zero energy building (NZEB) can achieve significant energy saving by reducing its air-conditioning load greatly. At the same time, an NZEB should also achieve a comfortable thermal environment. In this paper, a parallel-pipe type natural heat transfer air-conditioning terminal device is proposed and studied for use in NZEB. The terminal device is able to provide both heating and cooling (including sensible and latent cooling) for a building without noise or air disturbance. The advantages of the terminal device have been demonstrated by comparing with other air-conditioning terminals. Experimental data of the heating and cooling performance of the device under different operation conditions were collected and analysed. The calculation models for the heating and cooling capacities of the device were obtained through data regression analysis, and the flow resistance curve of the device was obtained by means of experimental measurement under various flow rates. In addition, comparison was made on the heating and cooling capacities between the device and a radiant floor that also features little noise or air disturbance. Results show that the heating and cooling capacities of the device were 41.5% and 46.8% higher than the maximum capacities of the radiant floor, respectively. This research laid a foundation for the engineering application of the air-conditioning terminal device.

scholarly journals Using buildings' foundation as a GHE in moderate climates

2020 ◽  
Author(s):  
Lazaros Aresti ◽  
Paul Christodoulides ◽  
Georgios A. Florides
Keyword(s):  
Heat Transfer ◽  
Reinforced Concrete ◽  
Heat Pumps ◽  
Scale Model ◽  
Space Heating ◽  
Zero Energy ◽  
Ground Source Heat Pumps ◽  
Heating And Cooling ◽  
Zero Energy Building ◽  
Energy Piles

<p>Shallow Geothermal Energy, a Renewable Energy Source, finds application through Ground Source Heat Pumps (GSHPs) for space heating/cooling via tubes directed into the ground. There are two main categories of Ground Heat Exchanger (GHE) types: the horizontal and the vertical types. Ground Heat Exchangers (GHEs) of various configurations, extract or reject heat into the ground. Even though GSHP have higher performance in comparison to the Air Source Heat Pumps (ASHPs), the systems high initial costs and long payback period have made it unattractive as an investment. GSHP systems can also be utilized in the buildings foundation in the form of Thermo-Active Structure (TAS) systems or Energy Geo-Structures (EGS), with applications such as energy piles, barrette piles, diaphragm walls, shallow foundations, retaining walls, embankments, and tunnel linings. Energy piles are reinforced concrete foundations with geothermal pipes, whereby the buildings foundations are utilized to provide space heating and cooling. Apart from energy piles, another EGS system can be achieved by the incorporation of the building’s foundation bed as a GHE. Foundation piles are not required in all constructions, but a building’s foundation bed is mandatory. This configuration is still based on the principles of the energy pile.</p><p>Energy piles have yet to be applied in Cyprus and, thus, a preliminary assessment considered and investigated before application would be useful. The potential of the GSHP systems by utilizing the building’s foundation through energy piles is considered here, for a moderate climate such as Cyprus, towards a Zero Energy Building. Typical foundation piles geometry in Cyprus consists of a 10m depth, a 0.4m diameter and reinforced concrete as a grout material, which is used at the foundation bed of the building. A typical dwelling in Cyprus is selected to be numerically modelled in this study. It is a three-bedroom, two-storey house with a 190m<sup>2</sup> total floor area, matching the thermal characteristics of a Zero Energy Building (i.e., U-values of 0.4W/m<sup>2</sup>/K on all walls and ceiling and 2.25 W/m<sup>2</sup>/K on all doors and windows, respectively). A full-scale model is developed in COMSOL Multiphysics software, to examine the energy rejected or absorbed into the ground by taking the heating and cooling loads of the typical dwelling in Cyprus. The convection-diffusion equation for heat transfer is used with the three-dimensional conservation of heat transfer for an incompressible fluid on all domains except the pipes, where a simplified equation is used. Different months in winter and summer are accounted for the simulations and the fluid-in – fluid-out temperature difference is presented. Finally, an economic evaluation of the systems examined above is presented, in order to check its viability. It is concluded that utilizing the dwelling’s foundations can be a better investment than using GHEs in boreholes.</p>

scholarly journals Analysis of indoor environment and performance of net-zero energy building with vacuum glazed windows

2021 ◽  
Vol 3 (1) ◽  
pp. 1-14
Author(s):  
Takao Katsura ◽  
Haruhiko Ito ◽  
Kirina Komuro ◽  
Katsunori Nagano ◽  
Saim Memon
Keyword(s):  
Heat Transfer ◽  
Thermal Environment ◽  
Primary Energy ◽  
Zero Energy ◽  
Transfer Coefficients ◽  
Zero Energy Building ◽  
Net Zero Energy ◽  
Net Zero Energy Building ◽  
Net Zero ◽  
Insulation Performance

The total energy and indoor thermal environment of an office building, which aims at the net-zero energy building, were measured and analysed. The annual total primary energy consumption of ‘Measurement’ was smaller than the value of ‘Calculation’ at design phase and achieved net-zero. The result of analysis of the thermal environment shows that the comfortable thermal environment was maintained. Also, the insulation performance and heat balance of the vacuum glazed windows in winter was evaluated. The overall heat transfer coefficients calculated by using the monitoring data were almost equal to the rated overall heat transfer coefficient and the high insulation performance of vacuum glazed windows was maintained even in the second year’s operation. In addition, the amount of heat gain due to solar radiation on the window surface was much larger than the amount of heat loss due to transmission. The vacuum glazed windows with high thermal insulation performance on the south side can reduce the heating load and contribute to the achievement of net-zero in the buildings.

scholarly journals Analysis of Net Zero-energy Building in Spain. Integration of PV, Solar Domestic Hot Water and Air-conditioning Systems

2014 ◽  
Vol 48 ◽  
pp. 828-836 ◽  
Author(s):  
Alessandro Gallo ◽  
Bélen Téllez Molina ◽  
Milan Prodanovic ◽  
José González Aguilar ◽  
Manuel Romero
Keyword(s):  
Air Conditioning ◽  
Hot Water ◽  
Zero Energy ◽  
Domestic Hot Water ◽  
Zero Energy Building ◽  
Net Zero Energy ◽  
Net Zero Energy Building ◽  
Net Zero ◽  
Air Conditioning Systems

scholarly journals Energy-Efficient Retrofit Measures to Achieve Nearly Zero Energy Buildings

2022 ◽  
Author(s):  
Nimish Biloria ◽  
Nastaran Abdollahzadeh
Keyword(s):  
Energy Efficient ◽  
Climatic Condition ◽  
System Optimization ◽  
Hvac System ◽  
Zero Energy ◽  
Heating And Cooling ◽  
Zero Energy Building ◽  
Net Zero ◽  
Ipcc Report ◽  
Ground Impact

Considering the 2021 IPCC report that justly attributes our deteriorating climatic condition to human doing, the need to develop nearly zero energy building (nZEB) practices is gaining urgency. However, rather than the typical focus on developing greenfield net-zero initiatives, retrofitting underperforming buildings could create significant scale climate positive impacts faster. The chapter accordingly discusses energy-efficient retrofitting methods under three categorical sectors—visual comfort (daylight-based zoning, shadings); thermal comfort and ventilation (solar radiation-based zoning, central atrium plus interior openings, insulation, and window replacement); energy consumption (efficient lighting system, and controllers, material and HVAC system optimization, PV panels as the renewable energy source). This chapter further substantiates these theoretical underpinnings with an implemented design scheme—an educational building within a cold semiarid climatic condition—to showcase the on-ground impact of these retrofitting strategies in reducing the energy used for heating and cooling and lighting purposes.

Adaptive Energy Optimization Toward Net-Zero Energy Building Clusters

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Philip Odonkor ◽  
Kemper Lewis ◽  
Jin Wen ◽  
Teresa Wu
Keyword(s):  
Energy Resources ◽  
Distributed Energy ◽  
Zero Energy ◽  
Operational Strategies ◽  
Operation Conditions ◽  
Zero Energy Building ◽  
Net Zero Energy ◽  
Net Zero Energy Building ◽  
Net Zero ◽  
Net Zero Energy Buildings

Traditionally viewed as mere energy consumers, buildings have adapted, capitalizing on smart grid technologies and distributed energy resources to efficiently use and trade energy, as evident in net-zero energy buildings (NZEBs). In this paper, we examine the opportunities presented by applying net-zero to building communities (clusters). This paper makes two main contributions: one, it presents a framework for generating Pareto optimal operational strategies for building clusters; two, it examines the energy tradeoffs resulting from adaptive decisions in response to dynamic operation conditions. Using a building cluster simulator, the proposed approach is shown to adaptively and significantly reduce total energy cost.

Conserving Energy by Expanding the Thermal Comfort Envelope

1978 ◽  
Vol 22 (1) ◽  
pp. 533-536 ◽  
Author(s):  
Frederick H. Rohles
Keyword(s):  
Thermal Comfort ◽  
Indoor Air ◽  
Air Conditioning ◽  
Thermal Environment ◽  
Thermal Conditions ◽  
Heating And Cooling ◽  
American Society ◽  
Psychrometric Chart ◽  
Sedentary Activities

Standard 55–74 entitled “Thermal Conditions for Human Occupancy” which is published by The American Society of Heating, Refrigerating, and Air Conditioning Engineers, (ASHRAE) defines an “acceptable thermal environment” as one in which “at least 80 percent of the normally clothed men and women while engaged in indoor sedentary or near sedentary activities would express thermal comfort.” This is pictured on the ASHRAE psychrometric chart as an envelope that includes dry bulb temperatures between 74°F and 77°F at relative humidities between 20% and 60%. The paper will describe five human factors approaches that have been used or are being considered to expand this envelope and thereby conserve energy. These are (1) the use of small radiant heaters which are installed in the modesty panels of desks so comfort may be attained at lower temperatures; (2) the demonstration that night set-back of thermostats to temperatures as low as 50°F do not effect sleeping patterns; (3) the role that interior decor can play in making people feel warmer; (4) the effect that temperature “swings” associated with solar heating and cooling has upon acceptance of the thermal environment and (5) the acceptance of a reduced quality of indoor air as a result of heating with an increased ratio of recirculated air to outside air.

Natural heat transfer air-conditioning terminal device and its system configuration for ultra-low energy buildings

2020 ◽  
Vol 154 ◽  
pp. 1113-1121 ◽  
Author(s):  
Haiwen Shu ◽  
Xu Bie ◽  
Hongliang Zhang ◽  
Xiaoyue Xu ◽  
Yu Du ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Air Conditioning ◽  
Low Energy ◽  
System Configuration ◽  
Terminal Device ◽  
Low Energy Buildings
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