Underground Air Research Articles

Responses of underground air and drip water geochemistry to meteorological factors: A multi-parameter approach in the Rull Cave (Spain)

Our research aims to assess the complex interactions between the elements that constitute and influence a cave system through the analysis of an extensive dataset of climatic and environmental parameters (222Rn, CO2, drip rates, chemical composition, and environmental isotopes) measured in air, water, and solid in the Rull Cave (southeastern Spain). Of particular importance is understanding the effect of rainfall and temperature on water and gas transport through the epikarst and the involved processes. Our results show that the cave gaseous concentration patterns do not only depend on the temperature-caused movement of air masses, but they can also be affected by abundant rainfall. The δ18O and δD composition of cave water also relies on such precipitations for the effective transfer of the rainfall signal into the cave, which can take between 3 and 7 days. The elemental ratios (Sr/Ca and Mg/Ca) show high responsiveness to the water drip rate, hinting that enhanced prior calcite precipitation (PCP) occurs at slower drip rates. Despite this, and regardless of drip rates, calcite saturation indices follow a seasonal variation pattern inversely proportional to the cave air CO2 concentration, while δ13C-DIC is proportional. Our results show how the interlinkage between these multiple components defines the dynamics of the atmosphere-soil-cave system. Cave monitoring is then essential to understand the karstic vadose zone, which is highly sensitive to climatic influence and its changes.

Towards a net-zero-energy building with smart control of Trombe walls, underground air ducts, and optimal microgrid composed of renewable energy systems

In recent years, permanent outages and lack of access to electricity have been significant problems in most cities of Iran. The increasing growth of fossil fuel consumption made it necessary to change the design of buildings. Designing a net-zero energy building (with natural ventilation and renewable energy systems) is a solution for reducing fossil fuels. In this paper, dynamic energy modeling of the building for the smart operation of the trapezoidal Trombe wall and underground air ducts is performed. In the first step, the Trombe Zones are considered for heating. Then the combination of the Trombe zones with underground air ducts for cooling is simulated. Then the system combination with a solar hot water system to supply hot water energy is evaluated. Finally, the economic analysis of the optimal hybrid system (with a photovoltaic system, wind turbine, battery, and inverter) for supplying the electricity of the building equipped with both passive energy strategies was evaluated by Homer software. The results show that by integrating the Trombe wall, the heating load is reduced by 44 %, and by integrating a coupled geothermal cooling system with the air duct and the Trombe wall, the cooling load is reduced by 39%. Also, the net present cost over the 25-year life of the optimized renewable system is reduced by about 12.5% due to both passive strategies. The average daily electricity energy demand of the base building is equal to 86.37 kWh and for the passive building, it is equal to 67.49 kWh.

Environmental radon control in the 700 m underground laboratory at JUNO

The Jiangmen Underground Neutrino Observatory is constructing the world’s largest liquid scintillator detector, with a 20 kt target mass and approximately 700 m of overburden. The total underground space of civil construction is around 300,000 m3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document}, with the main hall comprising about 120,000 m3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document}, making it the largest experimental hall in the world. Maintaining a low radon concentration in the underground air is crucial for both human health and the accuracy of experiments involving rare decay detection, such as neutrino and dark matter experiments. To ensure human health and the integrity of neutrino physics experiments, the nominal radon concentration in the main hall must be kept below 200 Bq/m3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document} with a maximum value below 400 Bq/m3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document}. Introduction of fresh air from above ground can significantly lower radon concentration. A benchmark experiment conducted in the refuge room near the main hall revealed that the radon emanating from underground water is a significant source of radon in the underground air. The total underground ventilation rate is approximately 160,000 m3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document}/h of fresh air with about 30 Bq/m3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document}222\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{222}$$\\end{document}Rn from the bottom of the vertical tunnel after the installation of powerful fans. Of this, 55,000 m3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document}/h is used for ventilation in the main hall. As a result of these measures, the radon concentration inside the main hall has decreased from 1600 Bq/m3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document} to below 200 Bq/m3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^3$$\\end{document} under stable working conditions, with exceptions during rare adverse weather events or fan failures. The employed strategies to control radon concentration in the underground air are described in this paper.

Pilot Study on Underground Air Temperature for Interior Thermal Comfort of Building in Malaysia

The purpose of this study is to assess the methods for achieving thermal comfort by utilising underground or subsurface air temperature. The goal of the research is to identify the efficiency of basement design as interior thermal comfort strategy in Malaysia. Two methodologies were employed, including computer modelling simulation and field data collection. The modelling simulation uses Energy Plus software to mimic and test the building’ thermal comfort, while the field data collection method employs a 1m × 1m × 1m physical model in an open space and the temperature was recorded using a globe thermometer. The temperature of underground at various depths was measured to establish the optimal temperature at which the earth may be used as a heat sink. The results from the physical model were then analysed to validate the results of the computer simulation. The result from the physical model and computer simulation shows that the underground temperature manages to decrease the indoor temperature. As a result, the presence of a basement that utilizes the temperature of the earth has significantly reduced the temperature of a specific room.

Research on the Evaluation of Air Quality in Underground Coal Mines Based on a Generalized Contrastive Weighted Comprehensive Scale Index Method

In this study, an optimization model was established based on the generalized contrastive weighted comprehensive scale index method. This model gives the evaluation indicators of SO2, NOx, CO, and TSP. It also innovatively introduces gas, the most harmful substance in underground coal mines, into the evaluation indicators. Moreover, the obvious hazardous concentration limit is used as the third standard concentration of the model. The scale sub-indices and the weights of SO2, NOx, CO, TSP, and gas are calculated, leading to the comprehensive scale index. Finally, the classification standard of the underground air quality is determined. An underground excavation face in Shaanxi Province is used as an example for air quality assessment. The air quality is generally poor at the points close to the working face, while that at the points far away from the working face is generally better. Furthermore, air quality optimization measures are given for areas with poor air quality.

Improving Citizens’ Health in Underground Public Interior Spaces Through AI Powered Green Walls

In almost 600 BC, the Green Walls concept was presented. Most of theprevious research has proved that the use of green walls in different types ofinterior spaces has its considerable merits in improving users’ overall health andproductivity. Interior Designers seem reluctant to integrate green walls inunderground spaces due to its drawbacks as one of the most expensive man-madewalls, needing scheduled water requirements, and its susceptibility to adversitiessuch as fungi growth.The current study offers an intelligent solution predicting the performanceof self-sustainable green wall systems improving underground air quality. Thesystem is mitigating the issue of the green wall’s short life span. Thesustainability of green walls and air quality in underground interior spaces isinvestigated by applying IoT and AI technologies.

Field tests and analyses of thermal and humidity environment and heating and cooling capacity of air intake tunnels into underground plants

The underground air intake tunnel is a natural source of heat and cold that can be utilised to significantly condition the air entering the underground plant, thereby reducing the energy consumption of the plant. The heat and humidity environments of three underground tunnels were tested in winter and summer. The tunnels belong to Jiangxi Hongping Hydropower Station, which has significant cooling and heating characteristics in the air intake tunnel, Sichuan Xiluodu Hydropower Station, the world’s largest underground power station, and Hainan Qiongzhong Hydropower Station, the southernmost in China. The heat and humidity exchange pattern between the underground air intake tunnel of the power station and the air was analysed, including temperature and humidity trends, condensation zoning, inter-seasonal thermoregulation effect. Furthermore, the cooling and heating capacity of the air intake tunnel was calculated and analysed. The results show that: the greater the length and cross-sectional area of the tunnel, the greater the cooling and heating quantity; there is a noticeable difference in heat transfer capacity between different air intake tunnels, and the tunnel length is not a decisive factor for the heat transfer capacity, the heat transfer capacity (enthalpy difference) per unit mass flow rate of air in the air intake tunnels of Jiangxi (1500 m) is more than twice that of Sichuan (2800 m); the test cooling capacity of the Hainan (1400 m) tunnel reaches 606 kW (while the plant chiller rated cooling capacity of 2082 kW), the air intake tunnel can be used as an underground plant energy-efficient air conditioning, the equipment selection of plant mechanical air conditioning should take into account the air handling capacity of the air intake tunnel.

Temperature Control Algorithm of Underground Air Conditioning in Station

Aiming at the air-conditioning temperature control of underground station, the air-conditioning temperature controller of underground station is designed based on proportional-integral-differential neural network, the bat algorithm is used to select the initial weights, the radial basis function neural network prediction model is used to optimize the design of the predictor, and the designed control system is simulated on the MATLAB simulation platform. The simulation results show that the dynamic characteristics and steady-state characteristics of the PID controller optimized by bat algorithm are better than those of the PID controller tuned by conventional methods. After optimization by radial basis function neural network prediction model, the rapidity and stability of controller are effectively improved.

Experimental Study on the Mechanical and Permeability Properties of Lining Concrete Under Different Complex Stress Paths

A promising large-scale energy storage is underground compressed air energy storage (CAES) in lined rock caverns. To ensure the safety and stability of storage caverns because of the influence of periodic injection during production, it is crucial to understand the mechanical behavior of lining concrete under different complex stress paths. In this study, three types of uniaxial compressive fatigue test and uniaxial creep test were conducted on concrete. The following conclusions were obtained from the results. 1) The irreversible deformation after the interval was larger than that before the interval in the discontinuous multi-step cyclic loading (DMCL) test. 2) Loading velocity significantly influenced concrete fatigue, and the irreversible deformation in the cycle of low loading velocity was greater than that in the cycle of high loading velocity. 3) The residual strain increased with an increase in stress level. 4) The creep strain increased with an increase in stress level during the multi-step creep loading test; the fractional derivative results were more consistent with the experimental results. 5) The permeability of concrete increased rapidly under the influence of an external force when the stress level exceeded 0.73.

PRE-COOLING / PRE-HEATING CHARACTERISTICS OF THE EARTH-TO-AIR HEAT EXCHANGER SYSTEM IN LONG-TERM OPERATION (PART 2): INVESTIGATION OF ACTUAL CONDITION OF AIR ENVIRONMENT IN UNDERGROUND AIR TUNNEL THROUGH FIELD MEASUREMENT AND CFD ANALYSIS IN SUMMER

In this study, we aim to propose the optimal operation method of an earth-to-air heat exchanger (EAHE). As a first step, in this paper, we investigated the relationship between the occurrence of condensation and air pollution by fungi in the underground air tunnel of an actual building. Firstly, we evaluated of condensation in the underground air tunnel based on actual measurement and unsteady CFD analysis. Secondly, exhaustive investigation of fungal flora in the underground air tunnel was conducted by DNA analysis.

Experimental and numerical study on the cooling performance of a new earth-air heat exchanger(EAHE) system with a supply air static pressure chamber

Earth-air heat exchanger (EAHE) is a low-carbon device that use renewable energy to improve the thermal environment of buildings by heating/cooling the air with the help of the thermal inertia of the soil. However, the traditional earth-air heat exchanger has the problem of large fluctuations in air temperature with the outdoor air temperature fluctuations. A system that combines an air supply chamber with an EAHE is proposed to address this problem. The outdoor air first enters the underground air supply static pressure chamber for initial cooling, and then enters the EAHE treatment. To investigate the effect of this air supply static pressure chamber on the cooling performance of EAHE, a three-dimensional numerical model was developed in ANSYS Fluent and validated with field measurement data. Then comparative studies of the EAHE system with a supply air static pressure chamber and the traditionnal EAHE system were conducted under summer conditions in Chongqing (China). The results show that the air supply static pressure chamber can reduce the EAHE outlet air temperature fluctuation by 31.98% at the maximum under the continuous operation of different air volume systems for 7 days. At the same time, the cooling capacity can be increased by 19.89% at maximum compared with the conventional EAHE cooling capacity.

Optimization of the non-stop switchover system control for the main fans used in mining applications

A stable ventilation system is an essential guarantee for the efficient production and safety of underground workers. In order to solve the big changes in underground air quantity, gas accumulation, and other problems caused by mine main fans switchover. This paper proposes a non-stop switchover system of the mine main fans based on intelligent control and establishes a dynamic optimization model for the switchover process of the mine main fans. The equilibrium optimizer algorithm is improved by chaos mapping and opposition learning machine based on refraction principle to solve the model, and the simulation experiment is carried out with MATLAB. The results show that the proposed method can effectively mitigate the change of underground air quantity during the switchover process of mine main fans. In the 120 s of system operation, the change rate of underground air quantity is consistently within 0.4%, and the two mine main fans always work in the stable interval, which proves the system's high efficiency, stability and safety.

The Unwanted Heritage of Prefabricated Wartime Air Raid Shelters—Underground Space Regeneration Feasibility for Urban Agriculture to Enhance Neighbourhood Community Engagement

The article deals with the problematic heritage associated with the system of Nazi German underground air raid shelters currently located within the Polish state, in the Baltic port city of Szczecin. The unwanted heritage has been inventoried, archival materials collected, and comparative analyses made of ways in which the underground space can be revitalised. An attempt was made to develop a typology of existing shelters and their locations. In order to overcome the negative associations with the warlike military space, positive system solutions were sought for the productive use of existing concrete structures located underground in central, easily accessible areas of the city districts. A process of upcycling the space was used to make ecologically efficient use of the material resources contained in the shelters. In order to activate the local community, a modular, hydroponic plant-growing system, adapted to the prefabricated spaces of the historical air raid shelters, was proposed. In this way, the central location of the underground structures within the boundaries of residential neighbourhoods was exploited. Such action strengthens the food sovereignty of the inhabitants, initiates bottom-up activity within the boundaries of the neighbourhood unit, and builds social ties in the spirit of a regenerative economy and positive sustainability.

Review of Polygeneration Schemes with Solar Cooling Technologies and Potential Industrial Applications

The trend to reduce CO2 emissions in cooling processes has made it possible to increase the alternatives for integrating solar energy with thermal equipment whose viability depends on its adaptation to polygeneration schemes. Despite the enormous potential offered by the industry for cooling and heating processes, solar cooling technologies (SCT) have been explored in a limited way in the industrial sector. This work discusses the potential applications of industrial SCTs and classifies hybrid polygeneration schemes based on supplying cold, heat, electricity, and desalination of water; summarizes the leading SCTs, and details the main indicators of polygeneration configurations in terms of reductions on primary energy consumption and payback times. To achieve an energy transition in refrigeration processes, the scenarios with the most significant potential are: the food manufacturing industry (water immersion and crystallization processes), the beverage industry (fermentation and storage processes), and the mining industry (underground air conditioning).

Research on the Fault Diagnosis Method of Mine Fan Based on Sound Signal Analysis

The underground local fan and auxiliary fan also play a vital role in the underground air quality, compared with the system fan. However, the number of underground local fans and auxiliary fans is large and widely distributed, which is disadvantageous to adopt the same method of online monitoring and fault diagnosis method as the system fan. In order to find a new fault diagnosis method, which is cost-effective and reliable, this paper proposes a fault diagnosis method based on sound signal. It analyzes the source of fan noise and studies the overall scheme of mine fan fault diagnosis expert system based on sound signal. The fault expert system consists of four parts: signal acquisition and noise elimination, feature extraction, state recognition, and fault diagnosis. Its principle is briefly introduced. The denoising method of wavelet is adopted in this paper. Wavelet packet is used to extract the characteristics of sound signal, and the energy size and energy proportion of each frequency component are used as the basis of knowledge acquisition and reasoning. Through the analysis of the measured signals of the fan in the normal operating state, the feature vectors were extracted as the basis for the discrimination of the normal state after noise elimination. At the same time, the audio processing software was used to simulate the sound signals in three fault states. Then, the feature vector of the fault state is extracted, which is obviously different from that of the fan in the normal operation. As the basis of fault state analysis of the expert system, it lays the foundation for the realization of the expert system of mine fan equipment running state diagnosis.

Post Mining Application: Tuzluca Rock Salt Mine Therapy Center for Health Tourism

The rapid development of technology coupled with the increases in population led to requirement of raw materials. For that reason, the largest quantity of production is needed but the large production causes significant social, economic and ecological consequences regarding a sustainable mining activity. Preserving the relevant balances reveals the necessity of developing sustainable projects after mining. Thus, development or sustainable development should be defined not only as increasing the welfare level, but also as protecting human rights, political rights and ecological balance, and leaving a liveable world to future generations. Herewith present study, Tuzluca rock salt mine was been assessed. Due to being located on the Silk Road, Tuzluca (Igdir, Turkey) rock salt mine with its rich reserves and tenors has been of great economic importance since ancient times. Within the areas of this salt mine, the production is still being carried out but the relevant and safe areas are under project for salt therapy purposes. Due to the unique properties of the salt mine and underground air, and its therapeutic ability potential, these areas have been assessed for health tourism, viz. Speleotherapy and Halotherapy center. These treatments are known to be very beneficial for respiratory tract, ear, nose, throat and skin diseases within the framework of complementary medicine applications. However, we should herein note that mining activities carried out might bring significant consequences regarding the social and ecological structures of the region. With the ongoing increase in mining activities, it has enabled the necessary investments, employment, education, trade and infrastructure for the residential area to develop over time. Along with the present project, we have aimed at developing and providing a sustainable prosperity and a safe future after salt mining activities, also aiming at making significant contributions to the region.

Fast calculation model for heat and mass transfer in a deep-buried underground air tunnel using Z-transfer coefficient method

Deep-buried tunnels are widely used in underground space for transportation and air ventilation. Accurately predicting the heat and mass transfer process of the ventilation in a tunnel is conducive to the design optimization of air conditioning and utilization of thermal pressure for underground buildings. The air condensation process has an important impact on the variation of air parameters in the tunnel. The Z-transfer coefficient method cannot accurately calculate the air parameters when the air condensation process occurs. To resolve this problem, in this study, the computational domain is redefined and a fast calculation model is proposed for heat and mass transfer in a deep-buried underground tunnel. The calculation results of this model are in good agreement with the field test results. Moreover, when calculating the hourly parameters of ventilation for a year, the running time of the new model is less than half of the finite difference method model. Considering the hourly parameters of ventilation for a certain number of days, the new model has a higher calculation efficiency. In addition, a case study was conducted to demonstrate the significance of considering the air condensation process in the model. If the calculation results of the model considering air humidity and condensation are taken as a reference, the absolute error of air temperature at the tunnel exit and the relative error of the thermal pressure, calculated by the model ignoring air humidity, can respectively reach 1.94 °C and 34%.

Longitudinal Monostatic Acoustic Effective Bulk Modulus and Effective Density Evaluation of Underground Soil Quality: A Numerical Approach

In this study, we introduce a novel method using longitudinal sound to detect underground soil voids to inspect underwater bed property in terms of effective bulk modulus and effective density of the material properties. The model was simulated in terms of layered material within a monostatic detection configuration. The numerical model demonstrates the feasibility of detecting an underground air void with a spatial resolution of about 0.5 λ and can differentiate a soil firmness of about 5%. The proposed technique can overcome limitations imposed by conventional techniques that use spacing-consuming sonar devices and suffer from low penetration depth and leakage of the transverse sound wave propagating in an underground fluid environment.

Season dynamics of microclimate parameters in the premises for keeping suckling sows farm with different ventilation systems

The article investigated the dependence of the microclimate indicators in the premises for keeping suckling sows on the design features of the ventilation system. The annual dynamics of seasonal temperature fluctuations in both premises of the reproducer of the farm, as well as in the zone of piglets' vital activity, was recorded within the normal range. At the same time, when using the classical type of ventilation, the temperature indicators were significantly higher in summer compared to similar values in premises with a geothermal type of ventilation. At the same time, the amplitude of fluctuations in the annual dynamics of the piglet den temperature was higher in premises with an experimental type of ventilation relative to the traditional one and with a slight relative excess of the optimal value of the indicator by 0,1 ° C in the spring months. The temperature regime of the den of sows both in the study and in the control premises during the study period was characterized by uneven differences in off-season indicators: when using classical ventilation, the peak fell in the summer period, when using ventilation with underground air supply, in winter, however, without exceeding the optimal values. The air velocity in both rooms increased during the summer months. At the same time, with the traditional system for creating a microclimate, a stable reliable excess of this indicator relative to the values of the studied system was recorded, as well as its excess of the norm in summer. For the studied system with underground air supply, on the contrary, low values were noted and extremely low in the winter season. Both ventilation systems ensured optimal air humidity during the study period. The carbon dioxide content tended to increase in the autumn months in both premises, however, it exceeded the norm only when using traditional ventilation during this period – by 0,02% vol. Average values of ammonia content were kept in the optimal zone during all seasons with a slight increase in concentrations in autumn. However, the experimental microclimate system allowed a significantly higher NH3 content than in control premises system in the summer months at 1,99 mg/m3 or 150,09%. The hydrogen sulfide content was optimal for both premises during the year. But the premises where the investigated air preparation system "Exatop" was installed significantly higher in the concentration of H2 S, by 64,81% (p<0,001) in spring, by 61,14% (p<0,001) in summer and by 43,00% (p<0,001) in autumn, relative to premises with a traditional air preparation system. Despite the shown dependence of the microclimate indicators on the type of ventilation, it should be noted that it is important to continue further studies of the influence of these factors. Key words: sow, piglet, type of ventilation, multiple births, piglet nest weight, safety, season.

Performance evaluation of a novel hybrid cooling system combining indirect evaporative cooler and earth-air heat exchanger

In this research, a new hybrid system combining indirect evaporative cooler and underground air tunnels has been proposed as an eco-friendly alternative for vapor-compression cooling cycles. Indirect evaporative cooling is an efficient thermal comfort cooling method in arid and semi-arid climates. Due to global warming and limited water resources, managing and monitoring of water consumption in evaporative coolers are of particular importance in these regions. In the present study, the cooling efficiency and water consumption of the proposed novel hybrid system are evaluated theoretically. To this aim, a mathematical model was developed for simulating the cooling performance of indirect evaporative cooler and earth-air heat exchanger systems. The fully implicit finite difference scheme was employed in computations. The simulations were validated against some available experimental and numerical data and a good agreement was obtained. The effect of the design parameters of the underground pipe on pre-cooling performance was studied. The results showed that coupling the underground heat exchanger to an indirect evaporative cooler not only improved cooling performance but also significantly decreased water consumption. Besides maintaining the desired thermal comfort level, our investigation indicated that the proposed system can decrease energy and water consumption by about 62% and 45%, respectively.