The effects of exhaust air vent location on thermal comfort inside a residential building equipped with an evaporative cooling system

The weather of Iraq has longer summer season compared with other countries. The ambient temperature during this season reaches over 50 OC which makes the evaporative cooling system suitable for this climate. In present work, the two-stage evaporative cooling system is studied. The first stage is indirect evaporative cooling (IEC) represented by two heat exchangers with the groundwater flow rate (5 L/min). The second stage is direct evaporative cooling (DEC) which represents three pads with groundwater flow rates of (4.5 L/min). The experimental work was conducted in July, August, September, and October in Baghdad. Results showed that overall evaporative efficiency of the system (two coils with three pads each pad of 3cm) reach to 167 % with the temperature difference between ambient and supply is 26.2oC. While it reached 122.7% (one coil with three pads ) with the temperature difference between ambient and supply is 16OC and reduced to 84.88% and 84.36% for IEC and DEC respectively.

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Analysis of the Performance of a Passive Downdraught Evaporative Cooling System Driven by Solar Chimneys in a Residential Building by Using an Experimentally Validated TRNSYS Model

Energies ◽

10.3390/en14123486 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3486

Author(s):

Andrés Soto ◽

Pedro Martínez ◽

Victor M. Soto ◽

Pedro J. Martínez

Keyword(s):

Natural Ventilation ◽

Energy Savings ◽

Cooling System ◽

Evaporative Cooling ◽

Residential Building ◽

Climatic Conditions ◽

Cold Climate ◽

Humid Climate ◽

Combined Model ◽

Evaporative Cooling System

Natural ventilation, combined with a passive cooling system, can provide significant energy savings in the refrigeration of indoor spaces. The performance of these systems is highly dependent on outdoor climatic conditions. The objective of this study was to analyse the feasibility of a passive, downdraught, evaporative cooling system driven by solar chimneys in different climatic zones by using an experimentally validated simulation tool. This tool combined a ventilation model and a thermal model of the dwelling in which an empirical model of a direct evaporative system made of plastic mesh was implemented. For experimental validation of the combined model, sensors were installed in the dwelling and calibrated in the laboratory. The combined model was applied to Spanish and European cities with different climates. In the simulation, values of cooling energy per volume of air ranging between 0.53 Wh/m3 and 0.79 Wh/m3 were obtained for Alicante (hot climate with moderate humidity) and Madrid (hot and dry climate), respectively. In these locations, medium and high applicability was obtained, respectively, in comparison with Burgos (cold climate with moderate humidity) and Bilbao (cold and humid climate), which were low. The evaluation of the reference building in each location allowed establishing a classification in terms of performance, comfort and applicability for each climate.

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Development of an evaporative cooler system applied to the air conditioning of urban buses

Scientia cum Industria ◽

10.18226/23185279.v8iss1p46 ◽

2020 ◽

Vol 8 (1) ◽

pp. 46-56

Author(s):

César Ramos Broliato ◽

Carlos Roberto Altafini ◽

Carlos Alberto Costa

Keyword(s):

Energy Consumption ◽

Thermal Comfort ◽

Air Conditioning ◽

Cooling System ◽

Evaporative Cooling ◽

Airflow Rate ◽

Total Energy Consumption ◽

A Value ◽

Evaporative Cooling System ◽

Evaporative Cooler

Air conditioning for buses is an important incentive tool for the public transport, since it offers comfort to passengers and stimulates the use of this kind of transport which is fundamental to improve urban mobility. Currently, air conditioning equipment for buses is the mechanical vapor compression (MVC) type. However, this kind of system has two main disadvantages: the high financial cost and power consumption by the vehicle engine. The purpose of this study is to develop an evaporative cooler for buses, which is a simple, environmental friendly, low-cost solution that does not use engine power for its operation. The first step was the design and construction of the prototype. The following step was to evaluate the built prototype through performing experimental tests. The prototype presented a saturation efficiency of approximately 70%, airflow rate of 421.5 m³/h and energy consumption of 98.4 W. After determining the prototype technical characteristics, the evaporative cooling system was developed for an urban bus, seeking to meet the air renewal required by ANSI/ASHRAE standard 62.1 and to promote the passenger’s thermal comfort as specified by ISO 7730 and ANSI/ASHRAE Standard 55. The thermal comfort provided by the new cooling system was evaluated through the PMV-PPD indexes. A value of 0.35 was obtained for the PMV index and the PPD index obtained a value of 7, indicating that approximately 93% of the passengers will be satisfied regarding their thermal comfort for the established environmental conditions. The evaporative cooling system had a total energy consumption of approximately 0.4 kW, which represents only 5% of the energy that would be consumed by a MVC system. Therefore, the evaporative cooling performance depends on the climatic conditions of the environment, especially humidity. However, when applied in favorable conditions (low humidity), the evaporative cooling system proved to be a viable solution to replace the MVC systems in buses air-conditioning application, where its main advantage is its positive cost-benefit and energy savings.

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Dehumidification Potential of a Solid Desiccant Based Evaporative Cooling System with an Enthalpy Exchanger Operating in Subtropical and Tropical Climates

Energies ◽

10.3390/en12142704 ◽

2019 ◽

Vol 12 (14) ◽

pp. 2704 ◽

Cited By ~ 5

Author(s):

Ramadas Narayanan ◽

Edward Halawa ◽

Sanjeev Jain

Keyword(s):

Thermal Comfort ◽

Cooling System ◽

Evaporative Cooling ◽

Individual Performance ◽

Coefficient Of Performance ◽

Evaporative Cooling System ◽

The One ◽

Air Conditioning Systems ◽

Tropical Climates ◽

The Impact

The technical and economic attractiveness of a solid desiccant based evaporative cooling system depend on several factors: Configuration of the system components and their individual performance, availability of cheap but reliable regeneration heat source. In the tropical and subtropical regions, the air conditioning systems are expected to address not only the sensible loads but also, and most importantly—the loads due to higher outside humidity levels that can severely affect the thermal comfort of the building occupants. This paper reports on the dehumidification potentials of solid desiccant based evaporative cooling systems with an enthalpy exchanger operating in subtropical and tropical climates. In particular, the study presents the cooling and dehumidification capabilities of the enthalpy exchanger observed through the impact of its sensible and latent effectiveness on the thermal comfort of the conditioned space. The key performance indicators are split into two groups: (1) the thermal comfort of the conditioned space, and (2) the coefficient of performance. It was found that this cooling system with enthalpy exchanger performed better than the one without enthalpy exchanger in terms of dehumidification; however, the impact depends on the climate where the system operates.

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