Investigation of energy recovery with exhaust air evaporative cooling in ventilation system

2017 ◽  
Vol 139 ◽  
pp. 439-448 ◽  
Author(s):  
Samar Jaber ◽  
Akram W. Ezzat
Keyword(s):  
Energy Recovery ◽  
Ventilation System ◽  
Evaporative Cooling

scholarly journals Energetic investigation of energy recovery technologies in air handling units

2018 ◽  
Vol 9 (1) ◽  
pp. 49-57
Author(s):  
L. F. Al-Hyari ◽  
M. Kassai
Keyword(s):  
Energy Consumption ◽  
Indoor Air ◽  
Energy Recovery ◽  
Ventilation System ◽  
Ambient Air ◽  
Existing Buildings ◽  
Exact Methods ◽  
Technical Data ◽  
Air Temperatures ◽  
Air Handling Units

The statistical data show that the application of active cooling is spread widely in residential and commercial buildings. In these buildings, the ventilation is significantly increased in the whole energy consumption. There are similar problems in the operation of post-insulation of existing buildings. In this case, the energy consumption of the ventilation system gives a major proportion of the whole building services energy consumption. The opportuneness of this research shows that the actual available calculation procedures and technical designing data are only rough approximations for analyzing the energy consumption of air handling units and the energy saved by the integrated heat or energy recovery units. There are not exact methods and unequivocal technical data. In previous researches, the production and development companies have not investigated the effectiveness of the energy recovery units under difference ambient air conditions and the period of defrost cycle when the heat recovery can only partly operate under difference ambient air temperatures. During this term, a re-heater has to fully heat up the ambient cold air to the temperature of supplied air and generate the required heating demand to provide the necessary indoor air temperature.

scholarly journals An analysis of the innovative exhaust air energy recovery heat exchanger

2018 ◽  
Vol 240 ◽  
pp. 02003 ◽  
Author(s):  
Marek Borowski ◽  
Marek Jaszczur ◽  
Daniel Satoła ◽  
Sławosz Kleszcz ◽  
Michał Karch
Keyword(s):  
Heat Exchanger ◽  
Energy Recovery ◽  
Energy Use ◽  
Dynamic Change ◽  
Ventilation System ◽  
Primary Source ◽  
Winter Period ◽  
Recovery Efficiency ◽  
Total Energy Consumption ◽  
Result Show

Heating, ventilation and air conditioning systems are responsible for a nearly 50% of total energy consumption in operated buildings. One of the most important parts of the ventilation system is an air handling unit with a heat exchanger for energy recovery which is responsible for effective and efficient energy recovery from exhaust air. Typically heat exchangers are characterised by the producers by heat and humidity recovery efficiency up to 90% and 75% respectively. But these very high values are usually evaluated under laboratory conditions without taking into account a dynamic change of outdoor and indoor air conditions significantly affecting the recovery efficiency. In this paper, results of thermal, humidity and enthalpy recover efficiency of innovative energy recovery exchanger have been presented. The analysed system allows adjustment of the humidity recovery especially useful in the winter period and forefends energy use for an anti-froze system of energy exchanger. Presented result show that analysed innovative system can achieve the value of thermal efficiency recovery higher than 90% and efficiency of humidity recovery about 80%. This is possible because the analysed system is able to work without the use of any primary source energy or other anti-freeze systems. Presented in this research unique solution is able to work without external anti-freeze systems even in extremely adverse outdoor air conditions such as minus 20°C and humidity 100% RH.

scholarly journals LOW-COST AND NON-INVASIVE ENERGY RECOVERY TECHNIQUES FOR PUBLIC RESIDENTIAL BUILDINGS MADE WITH GREAT PANEL STRUCTURES IN ITALY

2019 ◽  
Vol 14 (3) ◽  
pp. 23-46
Author(s):  
Frida Bazzocchi ◽  
Sara Ticci ◽  
Vincenzo Di Naso ◽  
Andrea Rocchetti
Keyword(s):  
Energy Recovery ◽  
Energy Savings ◽  
Residential Buildings ◽  
Low Cost ◽  
Ventilation System ◽  
Energy Performance ◽  
Residential Units ◽  
Technical Solutions ◽  
Tunnel System ◽  
Indoor Comfort

In Italy, a large stock of public housing was built during the 1970s and 1980s with industrialized/prefabricated techniques. These buildings have envelopes characterized by the presence of many thermal bridges and low transmittance values. In addition, they feature inefficient single heating systems in residential units and no cooling/ventilation systems. As a result, these buildings require urgent energy retrofitting actions, and it is therefore necessary to define procedures that will guarantee effective results. The possible interventions must be compatible with building construction techniques as well as be minimally invasive and inexpensive. There are only a limited number of technical solutions, considering that residents should not have to move out during the renovations. In most Italian climatic zones, current interventions are usually linked to external insulation and window replacement, leading to an improvement in energy performance and comfort only during winter. Internal comfort conditions tend to worsen in summer months because seasonal temperatures tend to increase by a few degrees. Therefore, solutions should be proposed that will improve both summer and winter conditions. This work proposes an energy recovery procedure applied to a representative building from the abovementioned period located in the Florence area and constructed with an industrialized system named the “tunnel system” (great panels structure). The procedure used in this study provides for the redevelopment of the envelope and the application of a simple mechanical ventilation system to achieve substantial energy savings and improved indoor comfort conditions.

Energy Use Comparison of Air Distribution Systems Serving a Section of a School Building

2012 ◽  
Author(s):  
Stillman Jordan ◽  
Randall D. Manteufel
Keyword(s):  
Total Energy ◽  
Distribution System ◽  
Energy Recovery ◽  
Distribution Systems ◽  
Energy Savings ◽  
Ventilation System ◽  
Space Distribution ◽  
Air Distribution ◽  
Displacement Ventilation ◽  
Humid Climate

An optimal air distribution design accomplishes both comfort and ventilation requirements while consuming as little energy as possible. This paper analyzes four different air distribution systems and technologies including single duct variable air volume air handlers, chilled beam cooling systems, total energy recovery wheels, displacement ventilation, and dedicated outside air systems; in an effort to determine the best air distribution system for a representative section of a school in hot and humid climate. The effectiveness of the air distribution systems is evaluated by analyzing how the different technologies take advantage of the natural convective properties of air to create a comfortable environment for the occupied region of the space. Distribution effectiveness and energy consumption must be weighed against considerations such as system complexity and ease of operation. This paper compares several alternative air distribution systems to a baseline single inlet VAV system that is commonly used in new schools designed today. Calculations show that the total energy recovery wheels result in a 16% energy savings over the baseline air distribution system because of the large amount of outside air required in school buildings. Chilled beams are not well suited for schools because of the large amount of outside air required by the space and the sophisticated design and operation needed to prevent condensation from occurring at the chilled beam. The results show that the air distribution system that consumes the least amount of energy is a displacement ventilation system. The system also inherently promotes better indoor air quality as it allows air to naturally rise out and return out of the space with minimal mixing of contaminates that may be recirculated within the room for others to breath. The displacement ventilation system’s overall energy savings of 20% over the baseline is mainly attributed to its total energy recovery wheel and the system’s ability to drastically reduce the cooling load seen by the air cooled chiller by effectively ventilating spaces using less outside air.

scholarly journals Design of a Passive Downdraught Evaporative Cooling Windcatcher (PDEC-WC) System for Greenhouses in Hot Climates

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2934 ◽  
Author(s):  
Marouen Ghoulem ◽  
Khaled El Moueddeb ◽  
Ezzedine Nehdi ◽  
Fangliang Zhong ◽  
John Calautit
Keyword(s):  
Relative Humidity ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Evaporative Cooling ◽  
Cross Flow ◽  
Flow Distribution ◽  
Average Error ◽  
Ambient Conditions ◽  
Mass Flow Rates ◽  
Computational Fluid Dynamics Cfd

A windcatcher is a wind-driven natural ventilation system that catches the prevailing wind to bring fresh airflow into the building and remove existing stale air. This technology recently regained attention and is increasingly being employed in buildings for passive ventilation and cooling. The combination of windcatchers and evaporative cooling has the potential to reduce the amount of energy required to ventilate and cool a greenhouse in warm and hot climates. This study examined a greenhouse incorporated with a passive downdraught evaporative cooling windcatcher (PDEC-WC) system using Computational Fluid Dynamics (CFD), validated with experimental data. Different hot ambient conditions of temperature (30–45 °C) and relative humidity (15–45%) were considered. The study explored the influence of different spray heights, layouts, cone angles and mass flow rates on indoor temperature and humidity. The average error between measurements and simulated results was 5.4% for the greenhouse model and 4.6% for the evaporative spray model. Based on the results and set conditions, the system was able to reduce the air temperature by up to 13.3 °C and to increase relative humidity by 54%. The study also assessed the influence of neighbouring structures or other greenhouses that influence the flow distribution at the ventilation openings. The study showed that the windcatcher ventilation system provided higher airflow rates as compared to cross-flow ventilation when other structures surrounded the greenhouse.

scholarly journals Data-Driven Models for Estimating Dust Loading Levels of ERV HEPA Filters

2021 ◽  
Vol 13 (24) ◽  
pp. 13643
Author(s):  
Seung-Hoon Park ◽  
Jae-Hun Jo ◽  
Eui-Jong Kim
Keyword(s):  
Indoor Air ◽  
Energy Recovery ◽  
High Efficiency ◽  
Ventilation System ◽  
Data Driven ◽  
Air Purification ◽  
Regression Equations ◽  
Pressure Drops ◽  
Dust Loading ◽  
Filter Dust

With increasing global concerns regarding indoor air quality (IAQ) and air pollution, concerns about regularly replacing ventilation devices, particularly high-efficiency particulate air (HEPA) filters, have increased. However, users cannot easily determine when to replace filters. This paper proposes models to estimate the dust loading levels of HEPA filters for an energy-recovery ventilation system that performs air purification. The models utilize filter pressure drops, the revolutions per minute (RPM) of supply fans, and rated airflow modes as variables for regression equations. The obtained results demonstrated that the filter dust loading level could be estimated once the filter pressure drops and RPM, and voltage for the rated airflow were input in the models, with a root mean square error of 5.1–12.9%. Despite current methods using fewer experimental datasets than the proposed models, our findings indicate that these models could be efficiently used in the development of filter replacement alarms to help users decide when to replace their filters.

scholarly journals Comparison of Heat Recovery Ventilator Frost Control Techniques in the Canadian Arctic: Preheat and Recirculation

2021 ◽  
Vol 246 ◽  
pp. 11010
Author(s):  
Justin Berquist ◽  
Carsen Banister ◽  
Mathieu Pellissier
Keyword(s):  
Energy Recovery ◽  
Heat Recovery ◽  
Ventilation System ◽  
Heat Energy ◽  
The Arctic ◽  
Control Technique ◽  
Outdoor Air ◽  
Control Techniques ◽  
Advantages And Disadvantages ◽  
Heat Energy Recovery

Air-to-air heat/energy recovery ventilators can effectively reduce the cost associated with ventilating a home. However, high indoor moisture levels, in conjunction with extreme temperature differences between the outdoor and indoor air can cause frost accumulation in the mechanical equipment, leading to performance degradation or failure. In this research, a demonstration house using a heat recovery ventilation system in Iqaluit, Nunavut, Canada was used to compare the performance of two frost control techniques: recirculation and electrical preheat. The advantages and disadvantages of each method are outlined to highlight the need to adapt southern strategies to ensure system functionality in the Arctic. The system was equipped with a heat recovery ventilator (HRV) with built-in recirculation technology to defrost the HRV, as well as two electric preheaters that can be used instead of recirculation and prevent frost formation. Between December 2018 and April 2019 the ventilation system’s performance was monitored for seven weeks while using either recirculation or electrical preheat. The experiments showed the ventilation system equipment consumed more absolute energy with electrical preheat than with recirculation as the frost control technique. However, when using recirculation, the ventilation system experienced more losses throughout the ventilation system, causing the whole building to consume more energy due to an increase in energy consumption by the home’s heating system. Moreover, the quantity of outdoor air that was restricted while using recirculation made electrical preheat the superior option for this ventilation system design. The energy use of the ventilation system with electric preheat enabled was 35% lower on a per volume of outdoor air basis. Contrary to some belief that preheating is a poor approach for frost control in heat/energy recovery ventilators, this research finds that preheating can be a more energy efficient method to provide ventilation if controlled well.

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