scholarly journals Determinación de profundidad óptima para intercambiadores de calor tierra-aire en Saltillo, Coahuila

2020 ◽  
pp. 1-7
Author(s):  
María Eugenia Molar-Orozco ◽  
Juan Ríos-Arriola ◽  
Gonzalo Bojorquez-Morales ◽  
Jaime Alonso Reyes-López
Keyword(s):  
Architectural Design ◽  
Thermal Environment ◽  
Electrical Energy ◽  
Periodic Variation ◽  
Environmental Cost ◽  
Winter Period ◽  
Geothermal Heat ◽  
Home Heating ◽  
Different Depths ◽  
Air Conditioning Systems

Saltillo Coahuila, due to the lack of an adequate architectural design, some homes do not meet the thermal environment conditions required during the winter period, it is estimated that 471,725 habitants are affected by temperatures until - 3.4°C, which causes morbidity problems, so that the need for the use of electromechanical air conditioning systems with electrical energy consumption of high economic and environmental cost arises. The objective of the work was to study the feasibility of applying a geothermal heat exchanger for home heating. Periodic variation of soil temperature at different depths was studied to determine the optimum by experimentally validated equations. An ideal depth of 3 m was determined due to a variation of 25 y 30% and lower excavation cost compared to depths of 6, 9 and 12 m.

scholarly journals Absorption and adsorption chillers applied to air conditioning systems

2010 ◽  
Vol 31 (2) ◽  
pp. 77-94 ◽  
Author(s):  
Agnieszka Kuczyńska ◽  
Władysław Szaflik
Keyword(s):  
Heat Source ◽  
Air Conditioning ◽  
Coefficient Of Performance ◽  
Cooling Power ◽  
Geothermal Heat ◽  
Pump System ◽  
Desorption Process ◽  
Heat Pump System ◽  
Adsorption Chiller ◽  
Air Conditioning Systems

Absorption and adsorption chillers applied to air conditioning systemsThis work presents an application possibility of sorption refrigerators driven by low temperature fluid for air conditioning of buildings. Thermodynamic models were formulated and absorption LiBr-water chiller with 10 kW cooling power as well as adsorption chiller with silica gel bed were investigated. Both of them are using water for desorption process with temperatureTdes= 80 °C. Coefficient of performance (COP) for both cooling cycles was analyzed in the same conditions of the driving heat source, cooling waterTc= 25 °C and temperature in evaporatorTevap= 5 °C. In this study, the computer software EES was used to investigate the performance of absorption heat pump system and its behaviour in configuration with geothermal heat source.

Use of Solar Desiccant Air-Conditioning Systems in Commercial Buildings

Solar Energy ◽  
2005 ◽  
Author(s):  
Anthony Domenic Calderone ◽  
Mir-Akbar Hessami ◽  
Stefan Brey
Keyword(s):  
Air Conditioning ◽  
Greenhouse Gas Emission ◽  
Electrical Energy ◽  
Sole Source ◽  
Solar Thermal ◽  
Commercial Building ◽  
Solar Thermal Energy ◽  
Cooling Cycle ◽  
Solar Thermal Collectors ◽  
Air Conditioning Systems

Desiccant air conditioning systems provide an environmentally friendly alternative to the traditional methods of conditioning a building’s internal environment. Whilst conventional air conditioning systems rely on electrical energy to drive the cooling cycle, desiccant cooling is a heat driven cycle. As such, desiccant cooling provides an opportunity to be coupled with solar thermal collectors to reduce energy demands. This paper discusses the potential for a desiccant cooling cycle utilising solar thermal energy as the sole source of heat for regeneration of the desiccant. The study demonstrates that under the assumed design conditions this system will theoretically not require a regeneration heater. Installation of such a system in a commercial building would be extremely beneficial in reducing building’s energy consumption and therefore greenhouse gas emission.

scholarly journals Influence of Solar Reflectance and Renewable Energies on Residential Heating and Cooling Demand in Sustainable Architecture: A Case Study in Different Climate Zones in Spain Considering Their Urban Contexts

2019 ◽  
Vol 11 (23) ◽  
pp. 6782 ◽  
Author(s):  
Maria-Mar Fernandez-Antolin ◽  
José-Manuel del-Río ◽  
Roberto-Alonso Gonzalez-Lezcano
Keyword(s):  
Renewable Energy ◽  
Architectural Design ◽  
Research Work ◽  
Cold Climate ◽  
Large Temperature ◽  
Winter Period ◽  
Climate Zones ◽  
Solar Reflectance ◽  
Hot Climate ◽  
Urban Contexts

In this research work, energy simulation was used as a forecasting tool in architectural design. It includes the study of a multi-family residential building in five different climate zones of Spain, i.e., A4 (very hot climate zones), B4 (hot climate zones), C4 (moderate climate zones), D3 (cold climate zones), and E1 (very cold climate zones). The authors accomplished a sensitivity analysis in order to identify the influence of passive strategies (i.e., with regard to solar reflectance) and renewable energy (i.e., with regard to aerothermal energy) on indoor temperatures and energy demands. The increment in indoor temperatures depends on the neighboring buildings so that effect of urban contexts as a source of protection against sunlight is also considered. The increment in the albedo (i.e., the solar reflectance) of the façade during the winter period produces little differences in indoor operative temperatures. On the contrary, during the summer period, it produces large temperature differences. Therefore, it is shown that colors significantly reduce temperatures from 1.24 to 3.04 °C, which means considerable annual energy savings. This research demonstrates that solar reflectance can reduce the air indoor operative temperature down to 4.16 °C during the month of May in the coldest climate zones. As a result of the simulations, it is noted that the coldest climate zones are influenced to a greater extent by the inclusion of their urban contexts in the simulations. However, the heating demand, without considering it, becomes lower. Therefore, ignoring the urban context produces important errors in the heating analysis (12.2% in the coldest climate zones) and also in the cooling analysis (39% in the hottest climate zones). Finally, the use of renewable energy in the configuration of a model with a high urban canyon (Hc), as well as with an east–west building orientation and a low albedo produces a difference of around 76% in the cooling costs within the hottest climate zones and around 73% in the heating costs within the coldest climate zones. The results of this study can be applied as a guideline in early architectural design.

scholarly journals Analysis of the Wind Environment to Improve the Thermal Comfort in the Colonnade Space of a Qilou Street Based on the Relative Warmth Index

2019 ◽  
Vol 11 (16) ◽  
pp. 4402 ◽  
Author(s):  
Xianfeng Huang ◽  
Zhen Lu ◽  
Zhixiang Zhuang
Keyword(s):  
Wind Speed ◽  
Thermal Comfort ◽  
Architectural Design ◽  
Thermal Environment ◽  
Transitional Space ◽  
Wind Environment ◽  
Warmth Index ◽  
Research Findings ◽  
Building Components ◽  
Computational Fluid Dynamics Cfd

By analyzing measurements of the thermal environment of a qilou (arcade building) street, this study used the relative warmth index (RWI) to evaluate the thermal comfort in the colonnade space of a qilou. The analysis of the influence of the temperature, humidity, and wind speed on the thermal comfort in the colonnade space of a qilou street was conducted, and it was shown that the ambient wind speed had a strong influence on the RWI, indicating that a proper increase in the wind speed positively affected thermal comfort in this space. Then, this study also analyzed the effects of different forms of qilou streets on the wind environment by employing computational fluid dynamics (CFD) and summarized the architectural design measures that can improve the thermal comfort, including adopting back chamfer, street gaps, and the appropriate sizing of building components. It was concluded that the wind environment of a qilou could be optimized in terms of these measures, and the average RWI value decreased by 0.06, effectively enhancing the thermal comfort in the colonnade space. The research findings are applicable toward designing a thermally comfortable environment in the transitional space.

scholarly journals Relation between energy use and indoor thermal environment in animal husbandry: a case study

2019 ◽  
Vol 111 ◽  
pp. 01042
Author(s):  
Matteo Bilardo ◽  
Lorenzo Comba ◽  
Paolo Cornale ◽  
Andrea Costantino ◽  
Enrico Fabrizio
Keyword(s):  
Relative Humidity ◽  
Animal Welfare ◽  
Thermal Environment ◽  
Animal Husbandry ◽  
Electrical Energy ◽  
Indoor Climate ◽  
Climate Conditions ◽  
Indoor Thermal Environment ◽  
Data Loggers ◽  
Energy Consumptions

Climate control is of the foremost importance in structures for intensive animal rearing because many animals (e.g. pigs and broilers) tolerate a small range of climate conditions (mainly air temperature and relative humidity) that may differ considerably from the outdoor environment. For this reason, the indoor climate in the majority of structures for animal husbandry is guaranteed by HVAC systems. On the one hand, the use of mechanical systems makes it possible to avoid production risks due to the unpredictability of the outdoor weather conditions and to maximize the feed efficiency, with positive effects on both the animal welfare and farm profit. On the other hand, the use of HVAC entails not negligible thermal and electrical energy consumptions. In literature, few data about the real thermo-hygrometric conditions and energy consumption of animal houses are present. In this work (in the framework of the EPAnHaus – Energy Performance certification of Animal Houses –project), the results obtained from a long-term monitoring campaign in two growing-finishing pig houses are presented. The performed measurements concerned environmental parameters and electrical power that were acquired during two production cycles (warm and cool seasons). For the environmental monitoring, both the buildings were equipped with temperature and relative humidity sensors embedded in portable data loggers (10 minutes logging time) that were placed in various spots inside the houses. Outdoor data were obtained through a weather station located near the test site. Concerning the energy monitoring, power transducers connected to portable data loggers (10 seconds logging time) were placed in the electric panel of each house to log the electrical energy consumptions due to ventilation, lighting and automatic feeding. The acquired data were used for carrying out analysis concerning the indoor thermal environment, its characterization in relation with the animal welfare, the electrical energy uses and the existing relations between all these aspects. The obtained data were used to evaluate the effectiveness of the HVAC system in guaranteeing the adequate indoor climate conditions (avoiding heat/cold stress conditions) and to identify electrical energy uses.

Evaluation of Thermal Environment and Indoor Air Quality in University Libraries in Vienna

2014 ◽  
Vol 899 ◽  
pp. 315-320 ◽  
Author(s):  
Gabriela Adam ◽  
Ulrich Pont ◽  
Ardeshir Mahdavi
Keyword(s):  
Thermal Environment ◽  
Environmental Study ◽  
Winter Period ◽  
Climate Data ◽  
University Libraries ◽  
Late 20Th Century ◽  
Outdoor Climate ◽  
Co2 Levels ◽  
The 19Th Century

This contribution presents the results of an indoor environmental study of university libraries in Vienna. Indoor climatic parameters (air temperature, relative humidity, and CO2 levels) in the main spaces of four different library buildings (two historic buildings from the 19th century, two buildings from the late 20th century) were monitored over a period of ten months. Furthermore, to obtain a general impression of the quality of the visual environment in these buildings, illuminance levels at selected locations were measured. The measured data was analyzed and enriched with additional calculated indicators (e.g., PMV/PPD). To put the monitored data in the proper context, recorded outdoor climate data was also taken into consideration. The findings point to a certain overheating risk during the summer period as well as increased CO2 levels during the winter period.

Near-Field Radiative Heat Exchange Analysis of a Spacecraft Waste Heat Converter Design

2012 ◽  
Vol 4 (2) ◽  
Author(s):  
Laurie Y. Carrillo ◽  
Yildiz Bayazitoglu
Keyword(s):  
Heat Exchange ◽  
Radiative Heat ◽  
Waste Heat ◽  
Thermal Environment ◽  
Near Field ◽  
Electrical Energy ◽  
Radiative Heat Exchange ◽  
Carnot Cycle ◽  
Field Plane ◽  
Cycle Efficiency

This paper presents a new design to convert spacecraft waste heat to electrical energy. The proposed device utilizes near-field radiative heat transfer incorporated with pyroelectric materials. To generate electricity, the pyroelectric materials are cyclically heated using spacecraft waste heat and cooled by the thermal environment of deep space (∼2.7 K). Near-field plane-to-plane radiative heat exchange within the device is calculated using a modified sphere-to-plane asymptotic approximation. This method is superimposed on multiple spheres to approximate a plane-to-plane environment. Silica and lithium fluoride coatings are considered in this study to maximize the near-field heat exchange. The efficiency of the device is 17% and 32% when compared to the Carnot cycle efficiency and the Curzon-Ahlborn efficiency, respectively. Initial results indicate that the device is promising but requires further development before it is manufactured for operational use. Suggestions for possible future developments to enhance the design are presented.

scholarly journals Improving performance of direct expansion air conditioning systems while reducing electricity consumption through using hybrid energy

2021 ◽  
Vol 289 ◽  
pp. 01014
Author(s):  
Ahmed Al–Okbi ◽  
Yuri Vankov ◽  
Hakim Kadhim
Keyword(s):  
Energy Consumption ◽  
Thermal Energy ◽  
Air Conditioning ◽  
Electrical Energy ◽  
Coefficient Of Performance ◽  
Electricity Production ◽  
Conventional System ◽  
Solar Thermal Energy ◽  
Continuous Power ◽  
Air Conditioning Systems

At the present time, operating hybrid air-conditioning systems that use solar energy to saving electrical energy while improving the performance has become necessary to protect the environment, reduce pollution and emissions caused by using fuels and gases. In Iraq, temperatures reach half the boiling point at summer, therefore the demand for air conditioning systems increases, air conditioning systems consume more than half of average electricity production which affects on reliability and stability of the electrical energy thus leads to a continuous power outage. So, the issue of using renewable energies becomes more attractive. Because of saving energy leads to ensuring the reliability of electricity and reduces the consumption of fuels and gases that pollute on the environment and negatively affect on the ozone layer. In the current research, the atmosphere of Baghdad city was used to collect solar thermal energy and convert it into thermal energy through an evacuated solar collector by water and combine it with a conventional air conditioner in the part that follows the compressor in order to reduce the electrical energy consumption on the compressor and increase coefficient of performance. Several tests were conducted on the proposed system to compare results with the conventional system and evaluate performance. The results showed that the coefficient of performance with the hybrid system became 8.97 more efficient instead of 4.27 compared to the conventional system, and the energy consumption decreased by 52%.

scholarly journals Progressive Development and Challenges Faced by Solar Rotary Desiccant-Based Air-Conditioning Systems: A Review

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1785
Author(s):  
Ranjan Pratap Singh ◽  
Ranadip K. Das
Keyword(s):  
Solar Energy ◽  
Air Conditioning ◽  
Energy Use ◽  
Operating Cost ◽  
Electrical Energy ◽  
Low Grade ◽  
Vapor Compression ◽  
Cooling Systems ◽  
Ongoing Research ◽  
Air Conditioning Systems

A rotary desiccant-based air-conditioning system is a heat-driven hybrid system which combines different technologies such as desiccant dehumidification, evaporative cooling, refrigeration, and regeneration. This system has an opportunity to utilize low-grade thermal energy obtained from the sun or other sources. In this paper, the basic principles and recent research developments related to rotary desiccant-based cooling systems are recalled and their applications and importance are summarized. It is shown that with novel system configurations and new desiccant materials, there is great potential for improving the performance and consistency of rotary desiccant systems; at the same time, the use of solar energy for regeneration purposes can minimize the operating cost to a great extent. Some examples are presented to demonstrate how rotary desiccant air conditioning can be a promising solution for replacing traditional vapor-compression air-conditioning systems. Recent advances and ongoing research related to solar-powered hybrid rotary desiccant cooling systems are also summarized. The hybrid systems make use of a vapor-compression system in order to have better operational flexibility. These systems, although they consume electrical energy, use solar energy as the principal source of energy, and hence, significant savings of premium energy can be obtained compared to conventional vapor-compression systems. However, further research and development are required in order to realize the sustainable operation of solar rotary desiccant air-conditioning systems, as solar energy is not steady. Reductions in capital cost and size, along with improvements in efficiency and reliability of the system is still needed for it to become a player in the market of air conditioning.

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