The work deals with the modeling and optimization physical variables in the design of air conditioning units serving rooms with high humidity - pool hall. Modeling is solved by creating software for a few basic compositions of air conditioning dehumidification devices. Calculations are programmed into the DLL in Delphi programming language.

<p dir="ltr">Building cooling and ventilation account for nearly 10% of the global electricity consumption. In fact, a recent study even showed that, globally, dehumidification consumes more energy than sensible cooling. One high-efficiency dehumidification technology is selective membrane dehumidification. Selective membranes allow water vapor transport but block air transport. There are two overarching gaps in the literature that are addressed in this dissertation: (1) vacuum membrane dehumidification (VMD) has been rigidly defined as an isothermal process and (2) literature on one of the most efficient VMD system designs, which I will refer to as the “dual module humidity pump,” is limited to ideal thermodynamic modeling (no experimental demonstration or practical system modeling in the current literature).</p><p dir="ltr">This work presents a novel system concept, referred to as the “Active Membrane Energy Exchanger” (AMX), which specifically couples VMD and air cooling into one process to provide the first non-isothermal VMD system concept. The present study provides a wholistic understanding of the benefits and limitations of the AMX approach through both thermodynamic system modeling and experimental protype development and demonstration.</p><p dir="ltr">System models developed in Engineering Equation Solver were used to compare the energy performance of the AMX to other HVAC technologies. These models showed that the AMX could achieve up to 25% annual cooling electricity savings in commercial buildings and up to 60% annual cooling electricity savings in 100% outdoor air applications. Experiments showed that combining cooling and dehumidification increased membrane permeance by up to 40% and increased dehumidification performance by 3-6%. Further demonstration showed the prototype could remove up to 45% of the humidity in the humid air flow but struggled to reject all of that vapor to the exhaust air (mass transfer imbalance). This discovery enabled a practical thermofluid model to estimate theoretical and practical COP limits, which were approximately 40 and 10, respectively. Additionally, a global sensitivity analysis on the new model showed that mechanical design is far more limiting to the performance than material design.</p><p dir="ltr">In summary, this dissertation develops and demonstrates a novel air conditioning technology, from system modeling to prototype demonstration. This work was funded and guided by industry partners, and the results of this dissertation are a major step towards real-world implementation.</p>

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No description available.

Serious social and economic disruptions are unfolding worldwide over the finite water and energy resources; hence, securing fresh water supply and employing renewable energy sources will help avoid catastrophic conflicts, continue modern lifestyles, and circumvent global warming and pollution. For this reason, a new method known as Humidification-Dehumidification (HDH) desalination process has been developed to address the challenge of water shortage. The aim of this research was to build the detailed mechanistic models with the increased capability to predict more accurately as well as to simulate and optimise the Multistage Humidification-Dehumidification (MHDH) desalination plant which is powered by solar energy. The poor prediction accuracy is major bottleneck for most of conventional models. Mechanistic models for HDH desalination process derived from non-linear mathematical equations offers a promising solution to overcome this challenge. This study proposes a mechanistic model which is formulated by combining the enthalpy equations with the models which govern the mass and heat transfer across a thin film that separates water and air phases within the humidifier and dehumidifier. The proposed model is validated by using the data which were obtained from the physical experiments. Moreover, an experimental rig was designed and fabricated to specifically generate the physical data. From the experimental and mathematical analysis, it was observed that the Recovery Ratio (RR) attained was increasing as temperature of the feed water increased. The RR was also increasing with the increase of dehumidifier’s surface area while it decreased with an increase of the packing size. Moreover, through a sensitivity analysis the highly influential parameters to the process model were identified to better understand the energy-efficient design principles and operating strategies for the maximum performance of the system. Finally, a two stages HDH hybrid system that uses solar and biomass as source of energy is proposed whereby, an optimisation problem is solved to achieve the optimum RR. A maximum of 2 stages were required for a system to operate optimally. / Commonwealth Scholarship Commission in the UK (CSC) under PhD Scholarships Plan for Low and Middle Income Countries

<p dir="ltr">Dehumidification is pivotal in contemporary society, especially for electronics and buildings. Electronic devices face operational risks due to moisture-related failures, with substantial economic impacts estimated between $0.5 and $5 billion annually from electrostatic discharge (ESD) alone. Around 20% of building electricity consumption is cooling-related, of which more than 50% is usually latent load (removing water in the air). Innovative water vapor-selective membranes offer a distinctive solution for managing latent loads, as the ideal energy requirement for separating water vapor with a membrane is much smaller than the energy required for condensing it out of the air. Vacuum membrane dehumidification (VMD) is a promising alternative dehumidification technology for its quick operation and excellent energy savings. It applies selective membranes that enable water vapor to pass but not air.</p><p dir="ltr">This work consists of investigating VMD systems in electronics and building dehumidification. Electronic devices, essential in modern society, face operational risks due to moisture-related failures, with substantial economic impacts estimated between $0.5 and $5 billion annually from electrostatic discharge (ESD) alone. Lack of relative humidity (RH) control is a leading cause of failure, with the critical RH threshold for clean electronic surfaces recognized at 60%. This study investigates Vacuum Membrane Dehumidification (VMD) as a novel dehumidification strategy, targeting the efficient control of RH within small electronic enclosures to mitigate moisture-induced failures. This work involves constructing a thermodynamic model for the VMD system, followed by the assembly of a physical prototype for empirical validation. The model integrates enclosure dimensions and membrane properties to simulate performance across various environmental conditions. Experimental validation of the model is conducted under controlled conditions to establish its accuracy. The results reveal that the VMD system achieves effective moisture removal with a Humidity Removal Fraction (HRF) of 30-65%, significantly influenced by the ambient RH and vacuum pressures. Energy optimization studies compare the VMD with conventional methods, illustrating superior performance in energy efficiency. The VMD system not only demonstrates its efficacy in RH management but also suggests a potential reduction in the operational energy requirements of electronic devices. This work establishes a foundation for membrane-based dehumidification technologies in electronic enclosure design, with broad applications across various sectors dependent on electronic systems.</p><p dir="ltr">The building dehumidification work is the first to integrate dual-module VMD with a residential vapor compression system, exploring recirculation air’s impact on energy consumption. Two membrane module designs (flat-sheet and hollow fiber membrane) are explored. A parametric study is conducted to assess the energy consumption of systems at different operation conditions. A practical way to size the membrane based on design conditions like AHRI 340/360 is introduced. Up to 17% of energy savings could be achieved in extremely humid weather conditions.</p>

Diploma thesis is focused on problematics of ventilation of swimming pool halls. Thesis describes the design of air handling units for swimming pool halls and operation risks. It presents different variants of ventilation with mentioned advantages and disadvantages of individual technical solutions. A swimming pool air handling unit was measured in real conditions as a part of experimental solution. The goal of measuring was to analyze thermal efficiency of cross flow heat exchanger aswell as to monitor working modes and functions of unit. Based on informations gathered during experimental measuring, two different variants of ventilation were designed. Both designs are evaluated economically during extreme weather conditions and during the whole year.

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In this thesis, experimental and numerical studies have been carried out to investigate the performance of a solar desalination system working on humidification-dehumidification principle under the climatological conditions of Ankara, Turkey. The desalination unit was configured mainly by a double-pass flat plate solar air heater with two glass covers, pad humidifier, storage tank and dehumidifying exchanger. The system used in this work is based on the idea of closed water and open air cycles. A computer simulation program based on the mathematical model was developed by means of MATLAB software to study the effect of different environmental, design, and operational parameters on the desalination system productivity. In this simulation program, the fourth order Runge-Kutta method was used to solve the energy balance equations simultaneously and numerically. In order to compare the obtained theoretical results with experimental ones and validate of the developed mathematical model of the system, an experimental study has been carried out. For that, an experimental set-up was designed, constructed and tested at the solar house of the Mechanical Engineering Department of METU. In addition, the existing solar desalination system was integrated with an evacuated tubular solar water heater unit (closed water circulation) and performance of the system has been studied experimentally.

The building sector has become the largest consumer of end use energy in the world, exceeding both the industry and the transportation sectors. Extensive types of energy saving techniques have been developed in the past two decades to mitigate the impact of buildings on the environment. Instead of the conventional active building environmental control approaches that solely rely on the mechanical air conditioning systems, increasing attention is given to the passive and mixed-mode approaches in buildings. This thesis aims to explore the integration of passive cooling approaches and active air conditioning approaches with different dehumidification features, by making effective use of the information on: 1) various dynamic response properties of the building system and mechanical plants, 2) diverse variations of the building boundary conditions over the whole operation process, 3) coupling effect and synergistic influence of the key operational parameters, and 4) numerous parameter conflicts in the integrated active-passive operation. These issues make the proposed integration a complex multifaceted process operation problem. In order to deal with these challenges, a systematic approach is developed by integrating a number of advanced building/system physical models and implementing well established advanced dynamic optimization algorithms. Firstly, a reduced-order model development and calibration framework is presented to generate differential-algebraic equations (DAE) based physical building models, by coupling with the high-order building energy simulations (i.e., EnergyPlus) and implementing MLE+ co-simulation programs in the Matlab platform. The reduced-order building model can describe the dynamic building thermal behaviors and address substantial time delay effects intrinsic in the building heat transfer and moisture migration. A calibration procedure is developed to balance the modelling complexity and the simulation accuracy. By making use of the advanced modeling and simulation features of EnergyPlus, the developed computational platform is able to handle real buildings with various geometric configurations, and offers the potential to cooperate with the dominant commercial building modeling software existing in the current AEC industry. Secondly, the physical model for the active air conditioning systems is developed, which is the other critical part for the dynamic optimization. By introducing and integrating a number of sub-models developed for specific building components, the model is able to specify the dynamic hygrothermal behavior and energy performance of the system under various operating conditions. Two representative air conditioning systems are investigated as the study cases: variable air volume systems (VAV) with mechanical dehumidification, and the desiccant wheel system (DW) with chemical dehumidification. The control variables and constraints representing the system operational characteristics are specified for the dynamic optimization. Thirdly, the integrated active-passive operations are formulated as dynamic optimization problems based on the above building and system physical models. The simultaneous collocation method is used in the solution algorithm to discretize the state and control variables, translating the optimization formulation into a nonlinear program (NLP). After collocation, the translated NLP problems for the daily integrated VAV/DW operation for a case zone have 1605/2181 variables, 1485/2037 equality constraints and 280/248 inequality constraints, respectively. It is found that IPOPT is able to provide the optimal solution within minutes using an 8-core 64-bit desktop, which illustrates the efficiency of the problem formulation. The case study results indicate that the approach can effectively improve the energy performance of the integrated active-passive operations, while maintaining acceptable indoor thermal comfort. Compared to the conventional local control strategies, the optimized strategies lead to remarkable energy saving percentages in different climate conditions: 29.77~48.76% for VAV and 27.85~41.33% for DW. The energy saving is contributed by the improvement of both the passive strategies (around 33%) and active strategies (around 67%). It is found that the thermal comfort constraint defined in the optimization also affects the energy saving. The total optimal energy consumption drops by around 3% if the value of the predicted percentage dissatisfied (PPD) limit is increased by one unit between 5~15%. It is also found that the fitted periodic weather data can lead to similar operation strategies in the dynamic optimization as the realistic data, and therefore can be a reasonable alternative when the more detailed realistic weather data is not available. The method described in the thesis can be generalized to supervise the operation design of building systems with different configurations.