A Graphical Tool to Estimate the Air Change Efficiency in Rooms with Heat Recovery Systems

Meiss, Alberto; Padilla-Marcos, Miguel Ángel; Poza-Casado, Irene; Álvaro-Tordesillas, Antonio

doi:10.3390/su12031031

Cited by 10 publications

(4 citation statements)

References 21 publications

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“…An important issue is the fact that energy consumption by the construction sector will continue to grow. They are already the main energy-consuming sector [104][105][106][107][108]. Heating, ventilation, and air conditioning (HVAC) systems alone account for 40-60% of a building's energy needs [109][110][111][112], and the ventilation systems themselves account for 20-30% [113].…”

Section: Façade Decentralised Ventilationmentioning

confidence: 99%

Review of IAQ in Premises Equipped with Façade–Ventilation Systems

Zender–Świercz

2021

Atmosphere

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Poor indoor air quality affects the health of the occupants of a given structure or building. It reduces the effectiveness of learning and work efficiency. Among many pollutants, PM 2.5 and 10 dusts are extremely important. They can be eliminated using mechanical ventilation equipped with filters. Façade ventilation devices are used as a way to improve indoor air quality (IAQ) in existing buildings. For their analysis, researchers used carbon dioxide as a tracer gas. They have shown that façade ventilation devices are an effective way to improve IAQ, but require further analysis due to the sensitivity of façade ventilation devices to the effects of wind and outdoor temperature. In addition, legal regulations in some countries require verification in order to enable the use of this type of solution as a way to improve IAQ in an era characterised by the effort to transform buildings into passive houses (standard for energy efficiency in a building).

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Section: Façade Decentralised Ventilationmentioning

confidence: 99%

Review of IAQ in Premises Equipped with Façade–Ventilation Systems

Zender–Świercz

2021

Atmosphere

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“…With respect to energy consumption, buildings are the main consumers, up to 40% of the worldwide energy demand. Around 40%–60% of each building's demand for energy goes for the heating, ventilation, and air‐conditioning systems and 20%–30% goes for the ventilation systems only 1,2 . To address this challenge, energy conservation via waste energy recovery is one of the effective methods that can successfully be implemented to decrease this worldwide growing need for energy 3–7 .…”

Section: Introductionmentioning

confidence: 99%

“…Around 40%-60% of each building's demand for energy goes for the heating, ventilation, and air-conditioning systems and 20%-30% goes for the ventilation systems only. 1,2 To address this challenge, energy conservation via waste energy recovery is one of the effective methods that can successfully be implemented to decrease this worldwide growing need for energy. [3][4][5][6][7] The use of centralized energy-recovery ventilation systems in new buildings is possible.…”

Section: Introductionmentioning

confidence: 99%

Theoretical and experimental investigation of a heat pipe heat exchanger for energy recovery of exhaust air

Ali

Sarsam

2022

Heat Trans

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Heat pipes and two‐phase thermosyphon systems are passive heat transfer systems that employ a two‐phase cycle of a working fluid within a completely sealed system. Consequently, heat exchangers based on heat pipes have low thermal resistance and high effective thermal conductivity, which can reach up to the order of (105 W/(m K)). In energy recovery systems where the two streams should be unmixed, such as air‐conditioning systems of biological laboratories and operating rooms in hospitals, heat pipe heat exchangers (HPHEs) are recommended. In this study, an experimental and theoretical study was carried out on the thermal performance of an air‐to‐air HPHE filled with two refrigerants as working fluids, R22 and R407c. The heat pipe heat exchanger used was composed of two rows of copper heat pipes in a staggered manner, with 11 pipes per row. Tests were conducted at different airflow rates of 0.14, 0.18, and 0.22 m3/h, evaporator inlet‐air temperatures of 40, 44, and 50°C, filling ratios of 45%, 70%, and 100%, and ratios of heat capacity rate of the evaporator to condenser sections (Ce/Cc) of 1 and 1.5. For HPHE's steady‐state operation, a mathematical model for heat‐transfer performance was set and solved using MATLAB. Results illustrated that the heat transfer rate was in direct proportion with the evaporator inlet‐air temperature and flow rate. The highest HPHE's effectiveness was obtained at a 100% filling ratio and (Ce/Cc) of 1.5. The predicted and experimental values of condenser outlet‐air temperature were in good agreement, with a maximum difference of 3%. HPHE's effectiveness was found to increase with the increase in evaporator inlet‐air temperature and number of transfer units (NTU) and with the decrease in airflow rate, up to 33% and 20% for refrigerants R22 and R407c, respectively. Refrigerant R22 was the superior of the two refrigerants investigated.

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“…The design of more efficient ventilation systems and units will lead to a reduction in energy demand of buildings [3] but if these systems are not monitored, there is not sufficient information about the real performance of these systems [4]. Modern highefficiency heat recovery systems that ensure the temperature efficiency above 85% cover the significant part of the heating energy demand of the ventilation systems [5]. It means that the correct design and accurate operation of the heat exchanger of the air handling unit (AHU) plays the most important role in optimizing the energy consumption [6].…”

Section: Introductionmentioning

confidence: 99%

Continuous automated ventilation heat recovery efficiency performance assessment using building monitoring system

et al. 2021

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The performance of ventilation heat recovery has high impact to the total energy consumption of modern buildings and its sub-optimal performance results in a remarkable energy penalty. There are several issues, which can significantly affect the heat recovery efficiency such as the inaccuracy of sensors, errors in control systems, mechanical defects and incorrect setting of the system. In addition, the direct comparison of the designed and measured heat recovery efficiency is not necessarily meaningful due to varying boundary conditions e.g. mass flow rates. The main focus of this paper is to develop and demonstrate a simple automated method for monitoring the heat recovery efficiency of ventilation units using building monitoring system (BMS). As the supply and extract air mass flows and temperatures may differ from the calculated initial design parameters, the proposed solution is to analyse the heat recovery efficiency using the number of transfer unit (NTU) method. With this method the efficiency is always calculated by the limiting mass flow, meaning that the warm exhaust air can not transfer more energy to the cold supply air than it is able to contain. As a result, the NTU method gives us the possibility to continuously compare the result to the temperature efficiency declared by the producer of the unit. The developed method demonstrated that the application of NTU method enables identifying sub-optimal performance of ventilation heat recovery, which would not have been revealed by direct comparison of temperature efficiencies. In some cases, low measured temperature efficiency was associated with problems not connected to the heat recovery heat exchanger. The method also enabled to estimate the additional heating costs due to the decreased heat recovery efficiency.

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A Graphical Tool to Estimate the Air Change Efficiency in Rooms with Heat Recovery Systems

Cited by 10 publications

References 21 publications

Review of IAQ in Premises Equipped with Façade–Ventilation Systems

Review of IAQ in Premises Equipped with Façade–Ventilation Systems

Theoretical and experimental investigation of a heat pipe heat exchanger for energy recovery of exhaust air

Continuous automated ventilation heat recovery efficiency performance assessment using building monitoring system

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