Exhaust Air Stream Research Articles

Rotary kiln simulation for energy recovery: The precalciner cement kiln case

Cement production process is energy intensive both in terms of the thermal and electrical energy. In fact, energy demand accounts for about 40 % of operational costs. Significant heat losses are present even in modern plants, affecting negatively both on production costs and emissions. These losses are mainly due to the sensible heat in the hot flue gases and exhaust air streams used for cooling down the clinker (35 % of the process heat losses). Given the good quality of the available sensible heat in these streams (temperatures above 280 °C), a heat recovery system can be considered to increase the overall efficiency of the cement plant. The aim of this work is to create a simplified model of a cement rotary kiln to study the heat recovery optimization. Results were consistent with the temperature, pressure and flowrates ranges indicated in the literature. The model here proposed can be adapted to simulate other processes involving a rotary kiln. As a result of the study of the proposed case scenario, the plant was found to potentially generate 3.2 kWh/ton of clinker of electricity, equivalent to approximately 20 % of the total plant electrical consumption.

Gaseous contaminant transfer in membrane-based air-to-air energy exchangers

Membrane-based air-to-air energy exchangers (M−AAEEs) transfer heat and moisture between building exhaust air and fresh ventilation air streams through a membrane, thereby reducing the energy required for conditioning the fresh ventilation air. Energy exchangers are typically used in buildings with relatively clean building exhaust air, such as office buildings and schools. Recently interest in using energy exchangers in a wider range of buildings has grown, to reduce the energy consumption associated with the heating, ventilating, and air-conditioning (HVAC) systems in these buildings. However, if the building exhaust air is not clean, as would be the case for laboratories or factories, new risks are encountered when using energy exchangers. It is possible that gaseous contaminants in the exhaust air may also transfer along with the moisture through the membranes, contaminating the incoming fresh ventilation air. Current test standards provide a test procedure to determine the contamination of the fresh ventilation air by measuring the transfer of an inert tracer gas in an energy exchanger. However, the tracer gas test may not represent the transfer of common indoor air contaminants due to differences in their transport properties. Therefore, in this study, an experimental facility is developed to determine the transfer of seven different contaminants through two membranes (porous and dense) at different flow rates. Contaminant transfer is quantified using a parameter called the exhaust contaminant transfer ratio (ECTR), which gives the fraction of the contaminants transferred from the exhaust air to the fresh ventilation air. A theoretical model based on the effectiveness-number of transfer units (ε-NTU) correlation and moisture transfer resistance of the membrane is presented to determine transfer through porous membranes and validated with experimental results. The major contribution of this paper is that it presents a simple method to predict the transfer of different contaminants through a porous membrane based on the moisture transfer resistance of the membrane at different operating conditions. It is found that as contaminant diffusivity decreases, ECTR generally also decreases, and as the flow rate increases, ECTR decreases, which is consistent with the predictions from the correlation.

Experimental study of a heat recovery ventilator preheated by a Building Integrated Photovoltaic system in a cold climate

The use of heat recovery ventilators (HRVs) in cold climate housing is becoming increasingly common, to provide outside air to the occupied space while recovering heat from the exhausted air. However, frosting of the heat exchanger core impedes HRV operation in cold climate conditions. Strategies for defrosting the core include recirculating the exhaust airstream while stopping the supply of the outside air during the defrost cycle. Preheating the air using heating coils is also used, but its application is limited by the increased energy use of the preheater. This study aims to investigate the impact of a building integrated photovoltaic/thermal (BIPV/T) system on the HRV thermal performance by using it to preheat the outside air. In this experimental study, measurements of a heat recovery ventilator preheated by the BIPV/T system are carried out in a test cell of the Future Buildings Laboratory (FBL) at Concordia University in Montreal, Canada. The results are compared to a HRV without BIPV/T preheating. The relative humidity, temperature and airflow rate of the fresh air and exhaust airstreams are monitored at the inlet and outlet of the HRV. The experiments are conducted during two weeks from January 26th, 2023 to February 08th, 2023. The change of the sensible heat recovery effectiveness ∈ sens of the HRV, outside air outlet temperature T 2 from the HRV and outside air flow rate, ṁ1 and exhaust air flow rate ṁ4 are determined. The primary experimental results indicate that preheating the outside air by the BIPV/T system before entering the HRV can help to increase the outside air outlet temperature T 2 by up to 2.7°C at an outdoor temperature of -25 °C, and the sensible heat recovery effectiveness ∈ sens , outside air flow rate, ṁ1 (23L/s) and exhaust air flow rate ṁ4 (43L/s) of the HRV are kept constant at the same level with preheating by BIPV/T on the HRV at -5 °C to -25 °C of outdoor temperature.

Energetic and exergetic performance investigation of a cross-flow regenerative indirect evaporative cooler made up of aluminium plate heat exchangers

Evaporative cooling is an environmentally friendly and low-cost method to deliver cooling load in hot climates. It has been proposed as an alternative to traditional vapour compression systems, mainly due to its lower power consumption and the ability to provide cooling without the need for refrigerants. The present study investigates a novel regenerative indirect evaporative cooling system to address the high cooling demands in hot climates. The proposed unit consists of commercially available aluminium plate cross-flow heat exchangers. Within the study, system performance is simulated in MATLAB software and numerical results are validated with experimental testing results. In the analysis, the effects of exhaust-to-inlet air ratio, inlet air temperature and inlet air relative humidity on the system energetic and exergetic performance were investigated. Individual effects of the inlet parameters on the thermal, mechanical and chemical exergies of the inlet, product and exhaust air streams were also investigated. Maximum wet bulb effectiveness values were achieved as 0.99 and 1.06 for the single and double effect configurations, respectively. In all inlet air conditions, an optimal exhaust-to-inlet air ratio of 0.4 was found to maximize the cooling capacity. Maximum exergy destruction rate was 35W. On the other hand, yearly potential energy savings of 695 kWh was calculated by replacing a vapour compression system with the proposed regenerative evaporative cooler.

Performance characterization of M-cycle indirect evaporative cooler and heat recovery ventilator for commercial buildings – Experiments and model

Evaporative cooling systems in buildings can dramatically reduce greenhouse gas emissions due to their low energy consumption, lack of ecologically harmful refrigerants and their diverse applications. Indirect evaporative cooling (IEC) uses water in the secondary air stream to cool the primary air without adding humidity to the indoor environment. The Maisotsenko Cycle (M−Cycle) design of an IEC has the potential to approach dew-point on the primary air by pre-cooling the secondary air stream before extracting heat in cross-flow with the primary air. Separately, a variety of technologies exist for energy recovery in commercial buildings to pre-condition ventilation air. In this study a M−cycle heat and mass exchanger was used as a heat recovery ventilator (HRV) to recover energy from the exhaust air stream during winter and as an IEC during summer to cool the ventilation air. Experiments were performed by operating the full-size IEC/HRV system with a maximum air flow rate of 2210 m3/hr in conjunction with indoor and outdoor environmental chambers simulating respective environments. The experimental results showed HRV heating sensible effectiveness between 67 % and 63 % and IEC cooling total effectiveness between 81 % and 71 % with increasing air flow rates. A detailed numerical model was developed to predict the performance of the IEC/HRV over a large range of operating conditions. The IEC model simulates heat and mass transfer from water evaporation in the secondary air and potentially from condensation in the primary air during summer season operation. The HRV model simulates heat transfer and potentially mass transfer from secondary air condensation during winter season operation. The detailed physics-based model was compared with experimental data, and it predicted the performance with high accuracy for both summer and winter operating conditions. The average absolute errors for supply air temperature between the experimental results and model predictions were 0.2 °C in HRV winter mode and 1.0 °C in IEC summer mode. The validated IEC model was used to further explore the possibility of combined ventilation and passive space cooling without a supplemental air-conditioner. The analysis shows that utilizing IEC for summer operation offers high cooling COP and even the potential for passive space cooling, which is not possible with conventional energy recovery ventilators (ERV).

Contaminant Crossover in Residential Energy Recovery Ventilators: Mass Spectrometric Analysis and Introducing Remediation Measures

Energy recovery ventilators (ERV) are increasingly present in residential environments to enable energy-efficient provision of controlled outdoor air ventilation. In this work, we investigated pollutant transport through a typical residential ERV as a potential pathway for re-entrainment of indoor air pollutants into the outdoor ventilation air supplied to an indoor space. Specifically, we investigated the transfer of volatile organic compounds (VOCs) through the sandwiched membrane matrix of the ERV core, between two adjacent air streams. Pollutant transfer efficiency is calculated for experiments intentionally injecting two common indoor VOCs (acetone, isopropanol (IPA)) and the behavior of transfer is studied for different ERV exhaust and supply flowrates (supply, exhaust, balanced scenarios). Maximum pollutant transfer efficiency of 17% is recorded for isopropanol at balanced (equal supply and exhaust airflow rates) conditions at intake and exhaust air lines. Maximum pollutant transfer efficiency of 26% and a minimum of 5.3% for unbalanced CFM settings are obtained. For VOCs studies, we observed short response times of <10s from starting injection of VOCs into indoor exhaust air stream until the concentration at the indoor supply air stream reaches to steady state. This results concluded that, ERVs typically have a lower response time to pollutant re-entrainment.

Air-to-Air Heat and Moisture Recovery in a Plate-Frame Exchanger Using Composite and Asymmetric Membranes.

The present work studied an air-to-air exchanger comprising a flat plate module with a diagonal channel and a counterflow configuration for the air streams. The objective of this study was to remove moisture and sensible heat from an exhaust air stream by indirect contact with another air stream. The temperature and flow rate of the exhaust air was in the range of 40–80 °C and 1–5 L·min−1, respectively, and the fresh ambient air to exhaust air flow ratio was 1–5. An asymmetric porous membrane (P-MEM), a thin film composite membrane (C-MEM), and a kraft paper were used as the core for the heat exchange module. The most influential parameter was the humid air temperature, with a direct positive effect (50–60%) due to the increase in the kinetic energy of the water molecules. The other effective parameter was the flow rate of the humid gas with a reverse effect on the enthalpy exchanger performance (25–37%). The ratio of “fresh” air to “exhaust” air had the lowest positive effect (8–10%) on the total effectiveness. The sensible effectiveness of different membranes under the studied conditions was relatively the same, showing their similar heat conductivity. However, the kraft paper showed the best performance compared to the synthetic membranes due to having a porous/hydrophile texture. P-MEM with an asymmetric porous texture showed the closest performance to kraft paper. Furthermore, it was found that under limited conditions, such as higher temperatures (70 and 80 °C) and flow rates (5 L·min−1) for the humid air, the performance of P-MEM was a little better than the kraft paper. However, C-MEM with the lowest total effectiveness and overall heat transfer coefficient (150–210 W·m−2·K−1) showed that the hydrophile PEBAX layer could not contribute to moisture recovery due to its high thickness.

Bacteria Clean Exhaust Air Streams Cost-Efficiently

Bacteria Clean Exhaust Air Streams Cost-Efficiently

Experimental study of a string-based counterflow wet electrostatic precipitator for collection of fine and ultrafine particles

ABSTRACT Wet electrostatic precipitators (WESP) have been widely studied for collecting fine and ultrafine particles, such as diesel particulate matter (DPM), which have deleterious effects on human health. Here, we report an experimental and numerical simulation study on a novel string-based two-stage WESP. Our new design incorporates grounded vertically aligned polymer strings, along which thin films of water flow down. The water beads, generated by intrinsic flow instability, travel down the strings and collect charged particles in the counterflowing gas stream. We performed experiments using two different geometric configurations of WESP: rectangular and cylindrical. We examined the effects of the WESP electrode bias voltage, air stream velocity, and water flow rate on the number-based fractional collection efficiency for particles of diameters ranging from 10 nm to 2.5 μm. The collection efficiency improves with increasing bias voltages or decreasing airflow rates. At liquid-to-gas (L/G) as low as approximately 0.0066, our design delivers a collection efficiency over 70% even for fine and ultrafine particles. The rectangular and cylindrical configurations exhibit similar collection efficiencies under nominally identical experimental conditions. We also compare the water-to-air mass flow rate ratio, air flow rate per unit collector volume, and collection efficiency of our string-based design with those of previously reported WESPs. The present work demonstrates a promising design for a highly efficient, compact, and scalable two-stage WESPs with minimal water consumption. Implications: Wet Electrostatic Precipitators (WESPs) are highly effective for collecting fine particles in exhaust air streams from various sources such as diesel engines, power plants, and oil refineries. However, their large-scale adoption has been limited by high water usage and reduced collection efficiencies for ultrafine particles. We perform experimental and numerical investigation to characterize the collection efficiency and water flow rate-dependence of a new design of WESP. The string-based counterflow WESP reported in this study offers number-based collection efficiencies >70% at air flow rates per collector volume as high as 4.36 (m3/s)/m3 for particles of diameters ranging from 10 nm – 2.5 μm, while significantly reducing water usage. Our work provides a basis for the design of more compact and water-efficient WESPs.

Ammonia Concentrations and Emissions at Two Commercial Manure-Belt Layer Houses with Mixed Tunnel and Cross Ventilation

HighlightsAnnual average NH3 concentrations in two retrofitted manure-belt layer houses were 4.0 ±3.3 and 5.2 ±3.0 ppmv.Seasonal and diurnal variations were observed for NH3 concentrations (higher in colder seasons and early morning).Annual average NH3 emission rates from the two layer houses were 0.081 ±0.004 and 0.099 ±0.004 g d-1 hen-1.No consistent pattern was found for either seasonal or diurnal variations in NH3 emission rates.Abstract. Ammonia emission measurements at poultry houses are necessary to assess air quality and emission factors associated with poultry operations, but no data have been reported for manure-belt layer houses retrofitted from high-rise layer houses. Two commercial retrofitted manure-belt layer houses (both 121.9 m long, 19.5 m wide, and 7.7 m high; 170,000 bird nominal capacity each) in Ohio with mixed usage of tunnel and cross ventilation systems were continuously monitored for one year. The daily averages of the exhaust NH3 concentrations varied from 0.03 to 17.7 ppmv in house 1 and 0.37 to 14.4 ppmv in house 2 with annual means (±SD) of 4.0 ±3.3 and 5.2 ±3.0 ppmv, respectively. The NH3 emission factors based on the full year of data for houses 1 and 2 were 0.081 ±0.004 and 0.099 ±0.004 g d-1 hen-1 (12.5 ±10.1 and 15.2 ±10.6 kg d-1 house-1 or 24.9 ±20.0 and 31.1 ±23.4 g d-1 AU-1), respectively. Seasonal variations were observed for NH3 concentrations, with higher concentrations in winter and lower concentrations in summer. Within a day, NH3 concentrations were highest from 4:00 to 8:00 and lowest from 16:00 to 20:00. No consistent pattern was observed for seasonal or diurnal variations of NH3 emission rates. Higher NH3 concentrations and emissions were observed at the east and west exhaust air streams of the houses compared to the north and south exhaust air streams due to the unique configuration of the ventilation systems. NH3 emission was correlated with exhaust absolute humidity, hen caloric intake, feed consumption, and protein percentage of feed. Keywords: Ammonia emission factor, Diurnal variation, High-rise, Retrofitted poultry house, Seasonal variation, Spatial variation.

Enhancing the potential use of microparticulate insecticides through removal of particles from raw grain

The current study presents the design and evaluation of a laboratory device combining mechanical motion of wheat grain and turbulent air streaming inside a positive pneumatic conveyor system. The device recovers microparticulate nano-engineered alumina insecticide powders (NAIP) from treated grain. The particle removal efficiency of the conveying system was experimentally quantified by using a laboratory prototype assembled by attaching an electrostatic filter (EF) to the conveyors exhaust. Then, the NAIP particles detached from the grain inside the conveyor were drawn by the conveyors’ exhaust air stream into the EF, where particles bound to the electrodes due to electric charge differences. The NAIP particle load bound to the EF electrodes was removed and weighed to determine the efficiency of the wheat grain cleaning process. Our experimental results, under laboratory conditions, show that the recovery efficiency of the prototype averaged 98.0% (±1.4). Thus, the present study provides an innovative strategy to remove NAIP insecticide particles after storage, once their role as insecticide in stored grain has been fulfilled. This technology provides advancement in grain technology allowing the possibility to provide insecticide-free grain to the food market.

Development of a small-scale test facility for effectiveness evaluation of fixed-bed regenerators

Fixed-bed regenerators (FBR) transfer heat (and moisture) between supply and exhaust air streams in heating, ventilating and air conditioning (HVAC) systems to reduce building energy consumption. This paper presents a new small-scale testing facility to evaluate the performance (i.e. sensible effectiveness) of FBRs for HVAC applications. The major contributions of this paper are: development of a new small-scale experimental facility and methodology for testing FBRs, quantification of uncertainties, and verification of small-scale test data over a large range of FBR design conditions. A numerical model and two well-known design correlations are used to verify the results and testing methodology. The advantages of small-scale testing are that it requires low volume of conditioned airflow, has low uncertainty, requires less exchanger material and has a low cost per test. Moreover, the small-scale testing methodology of FBR would benefit heat exchanger manufacturers to perform detailed sensitivity studies and optimize the exchanger performance over a wide range of design and operating parameters prior to the fabrication of full-scale exchangers.

Outdoor air state that may cause moisture condensation in membrane-type total heat exchangers using different membrane materials

Total heat exchanger (THX) is an air-to-air heat exchanger with a heat/moisture exchanging core made of water vapor permeable membrane, it is used to reduce the building energy consumption by recovering both heat and moisture from ventilation air. In hot and humid climate, the membrane surface may get a temperature below the dew point of supply outdoor air, causing moisture condensation at the membrane surface, which may degrade the exchanger performance and increase the health risk. In this research, a mathematical model is built to describe the heat and moisture transfer in the core of a THX, the effects of membrane properties on moisture condensation are analyzed, and the critical outdoor air states for occurrence of the moisture condensation are calculated. The results show that large membrane adsorption constant and large maximum moisture uptake may restrain the moisture condensation, which occurs more easily at the intersection of the supply and exhaust airstreams. The optimal membrane properties are recommended based on a comprehensive consideration of the safety and economy.

Design criteria for outdoor air intakes and exhaust air outlets located on an external wall

Optimal placement of outdoor air intakes and exhaust outlets is a source control measure to avoid the degradation of air quality at the air intakes. Re-entrainment is an occasional air pollution instance that happens if pollutants in the exhaust air stream, after being discharged to outdoors, are transferred back to outdoor air intake location due to unfavorable meteorological conditions and inadequate positioning of the air intakes and exhaust outlets. In engineering practice, it is impractical to always conduct detailed dispersion modeling due to the complexity of airflow phenomena in the urban environments, and therefore, engineers rely on prescriptive design guidelines or simplified empirical models published in technical literature and regulation documents. Commonly, the design guidelines to avoid the re-entrainment phenomenon are for buildings with rooftop exhaust stacks, but the exhaust outlets might also be situated on the building façade. The objective of this paper is to overview the existing design guidelines for the placement of horizontal air intakes and exhaust outlets. Technical engineering literature, including international standards, codes, and guidebooks is reviewed to extract both qualitative and quantitative design guidelines relevant to the placement of air intakes and exhausts on an external wall.

Applications with semipermeable membranes for humidity recovery in HVAC systems

Both the sensible heat recovery and the combined heat and humidity recovery are state of the art. Of particular importance is the humidity recovery in winter season. The transfer of water vapor from the humidity-laden exhaust air to the very dry fresh air is very important for a good room air quality. However, all systems established on the market require that supply and exhaust air streams crosses within the device. Practical enthalpy recovery systems for plant concepts with local separation of supply and exhaust air are not available on the market until now. In order to close this gap, the ILK Dresden works on a R&D project. The objective is the development of a textile heat exchanger, which - integrated into circulatory composite systems - can transmit not only sensible heat but also humidity between spatially separated air streams. The functional principle is based on a liquid sorption process via semipermeable membranes. The current state of the development will be presented. Furthermore an outlook is given how it is intended to proceed in the project in further steps.

Experimental Analysis of Atypically Long Finned Oscillating Heat Pipe for Ventilation Waste Heat Recovery Application

Oscillating heat pipes (OHP) which are constructed from a serpentine-arranged capillary tube possess a desirable aerodynamic form factor and provide for relatively high heat transfer rates via cyclic evaporation and condensation of an encapsulated working fluid with no internal wicking structure required. In last two decades, OHP has been extensively investigated for its potential application in thermal management of various applications. This study presents an experimental investigation on the heat transfer performance of an atypically long finned OHP. The heat transfer performance of the proposed OHP was analyzed and compared with a bare tube OHP with similar overall dimensions. Results show that a unit row of finned OHP filled with n-pentane with fill ratio of 70% can recover up to (400±40) W of heat from a typical waste exhaust air stream. The additional pressure drop due to fins was estimated to be (6.8±2) Pa resulting in an increase of 1–2 W of fan power consumption. The average heat recovery rate via finned OHP was found to be almost 80% more than bare tube OHP filled with same working fluid with same fill ratio.

Experimental investigation and performance evaluation of a mixed-flow air to air membrane enthalpy exchanger with different configurations

This paper presents an experimental investigation and performance evaluation of a mixed-flow air to air membrane enthalpy exchanger with different flow configurations. The moisture diffusivity, water contact angle and elastic modulus of five porous membranes were first experimentally determined using a wet cup test method, a contact angle meter and the tensile test, respectively. The five porous membranes investigated consisted of two Polyvinylidene difluoride membranes with the mean pore diameters of 0.22 µm (PVDF22) and 0.45 µm (PVDF45) respectively, two Nylon membranes with 0.1 µm and 0.45 µm pore sizes respectively and one Polyethersulfone (PES) membrane with a 0.1 µm pore size. The optimal membrane was then identified and used to fabricate an enthalpy exchanger. Lastly, the performance of the enthalpy exchanger with different mixed-flow configurations was experimentally investigated. The results showed that the PVDF45 membrane offered the highest moisture diffusivity (1.91 × 10−6 ± 2.42 × 10−8 m2/s) with hydrophilic surface and a relatively high elastic modulus (4.97 × 108 ± 3.86 × 107 Pa). It was shown that the enthalpy exchanger with Z-shape flow of the supply air stream and И-shape flow of the exhaust air stream at an entrance ratio of 0.25 offered the best thermal performance as the sensible, latent and total effectiveness increased by 12.3%, 15.1% and 14.6% respectively, when the flow rate was 0.3 l/s, as compared to that of the pure cross flow. The same flow configuration was able to recover the highest energy among all configurations investigated.

Heat recovery from spray dryer exhaust air: An example from an infant formula factory installation

This article describes a successful installation of a heat recovery system at the exhaust air stream on a commercial spray dryer for infant formulae. The entrained product particles prohibit a straightforward heat exchanger setup. Therefore, special provisions have to be made to avoid fouling: a bag house filter prior to cooling of the exhaust air stream, and an exceptional heat exchanger design with a low on-flow gas velocity, thick fins, and wide gaps, which facilitate wet cleaning. The optimization of the heat integration of the recovered heat into the production line used the pinch point method as a structured approach. It recommended three temperature levels; namely for the supply of the tanks for the cleaning fluids (lye and acid) for the cleaning-in-place (CIP) procedure, the fluid bed inlet air heaters, and the main inlet air pre-heaters. After 1 year of operation, the control software has been adjusted to better consider the buffering characteristics of the CIP tanks, and to operate the preheaters with a seasonally floating setpoint to recover more heat in spring and in autumn.

Moisture diffusion measurement and evaluation for porous membranes used in enthalpy exchangers

Air-to-air membrane enthalpy exchangers using semi-permeable membranes are widely used in building ventilation systems to pre-condition the supply air by exchanging energy with the exhaust air stream. Moisture diffusivity is one of the most important properties of porous membranes. This property has a significant influence on the design and performance of membrane enthalpy exchangers. In this study, moisture diffusion resistances of five porous membranes were measured, and the effects of the membrane pore size on the moisture diffusivity were evaluated under different test conditions. The five porous membranes tested included: i) two PVDF (Polyvinylidene difluoride) membranes with mean pore diameters of 0.22 µm and 0.45 µm respectively, ii) two Nylon membranes with 0.1 µm and 0.45 µm pore sizes respectively, and iii) a PES (Polyethersulfone) membrane with a 0.1 µm pore size. A theoretical model to predict the effectiveness of a crossflow membrane enthalpy exchanger was also developed with respect to the latent heat transfer. The experimental results showed that the PVDF membrane with a mean pore diameter of 0.45 µm outperformed the others in terms of the moisture diffusivity. The results from the theoretical model of the enthalpy exchanger agreed well with those from the experiments reported in the literature. The latent effectiveness was found to be insensitive to the outdoor air conditions.

Numerical and experimental analysis of a natural ventilation windcatcher with passive heat recovery for mild-cold climates

In this work, a novel design incorporating a passive heat recovery device into a windcatcher was proposed and investigated using numerical and experimental analysis. The proposed system incorporates a rotary thermal heat recovery in the windcatcher channel. Computational Fluid Dynamics (CFD) was used to investigate the effect of the heat recovery device on the performance of the windcatcher, highlighting the capabilities of the system to deliver the required fresh air rates. The windcatcher model was incorporated to a 5m x 5m x 3m test room model representing a small classroom. The study employed the CFD code Fluent18 with the k-epsilon model to conduct the simulations. The numerical model provided detailed analysis of the airflow and temperature distribution inside the test room. A 1:10 scale prototype of the system was created and tested experimentally in a closed-loop subsonic wind tunnel to validate the CFD investigations. Despite the blockage of the rotary t heat recovery wheel, ventilation rates were able to provide adequate ventilation. In addition to sufficient ventilation, the heat in the exhaust airstreams was captured and transferred to the incoming airstream, raising the temperature between 1-4K depending on the indoor/outdoor conditions, this passive recovery has the potential to reduce demand on space heating systems. According to WBCSD, a recovery of 3 K from the exhaust stream to the inlet stream could generate energy savings up to 20% in heating costs. This shows that the concept has significant potential to be developed further, whereby the heat transfer properties of the system can be investigated and tested on a larger scale.