Determining the optimal terminal box airflow is a complex process which is influenced by various factors, such as weather condition, supply air temperature, primary air fraction and internal load. A guideline for determination of a cost efficient minimum airflow setpoint for VAV terminal box units is drawn in this research. The most efficient optimal minimum airflow setpoint should not be a fix setting, but should be changing with zone load and ventilation requirement. A fixed minimum airflow is used in conventional control strategies. The terminal box minimum airflow required is not a constant since the supply air temperature, fresh air fraction and zone load are different. It is important to set up the minimum airflow to ensure IAQ and thermal comfort and to minimize energy consumption. Analysis has been carried out to compare how the supply air temperature, fresh air fraction and zone load affect the minimum airflow setting of an exterior zone. And 30% of design airflow is not always a good number, and may cause comfort issue or ventilation problem. If the minimum airflow is set higher than required, terminal boxes will have significantly simultaneous heating and cooling, and consume more fan power in the AHUs. If the minimum airflow is set lower than required, indoor air quality (IAQ) will be a concern. Energy saving ratio study is conducted to estimate the energy saving benefit by implementing an optimized minimum airflow.

Indiana University-Purdue University Indianapolis (IUPUI) / Air handling unit systems are the series of mechanical systems that regulate and circulate the air through the ducts inside the buildings. In a commercial setting, air handling units accounted for more than 50% of the total energy cost of the building in 2013. To make the system more energy efficient and reduce amount of CO₂ gases and energy waste, it is very important for building energy management systems to have an accurate model to help predict and optimize the energy usage and eliminate the energy waste. In this work, two models are described to focus on the energy usage for heating/cooling coils as well as fans for the air handling unit. Enthalpy based effectiveness and Dry Wet coil methods were identified and compared for the system performance. Two different types of control systems were modeled for this research, and the results are shown based on occupancy reflected by the collected CO₂ data. Discrete On/O and fuzzy logic controller techniques were simulated using Simulink MATLAB software and compared based on energy reduction and system performance. Air handling unit located in the basement of one campus building is used for the test case of this study. The data for model inputs is collected wirelessly from the building using fully function device (FFD) and pan coordinator to send/receive the data wirelessly. The air handling unit modeling also is done using Engineering Equation Solver EES Software for the coils and AHU subsystems. Current building management system Metasys software was used to get additional data as model inputs. Moving Average technique was utilized to make the model results more readable and less noisy. Simulation results show that in humid regions where there is more than 45% of relative humidity, the dry wet coil method is the effective way to provide more accurate details of the heat transfer and energy usage of the air handling unit comparing to the other method enthalpy-based effectiveness. Also, fuzzy logic controller results show that 62% of the current return fan energy can be reduced weekly using this method without sacrificing the occupant comfort level comparing to the ON/OFF method. Air quality can be optimized inside the building using fuzzy logic controller. At the same time, system performance can be increased by taking the appropriate steps to prevent the loss of static pressure in the ducts. The implementation of the method developed in this study will improve the energy efficiency of the AHU.

The goal of this diploma thesis is to design a modular air handling unit based on determined requirements. Modular air handling units provide great flexibility for consultants when work-ing on a project. Modular air handling units are assembled using many sections (heater section, cooler section, humidification section, fan section, etc) which gives the consultant an advantage to use only those sections necessary for particular project.

This diploma thesis deals with the creation of visualization for testing lab for air conditioning unit. This unit was made by Strojírenský zkušební ústav. The visualization was programmed in the visualization and simulation program called ControlWeb. This application allows controlling, monitoring, storing and retrieving all necessary variables. Next part of diploma thesis discusses techniques of measurement, automation devices and visualization software.

The main aim of the Master project is a design of the guesthouse with wellness, which has nearly zero-energy consumption and is located in Velká Bíteš. For design is used ARCHICAD, for numeric is used DEKSOFT. This Master project consists of three parts. The first part focuses on the design of the guesthouse, the second part concentrates on a technical design and the third part focuses on the draft of different energy sources, its comparison and evaluation. Guesthouse is a three-story building with walkable flat roof. Wellness, cold rooms and massages are located in the basement. Other places of floor consist of sanitary facilities, technical rooms and common rooms. There are also guest rooms on the other floors and a conference hall on the third room. This final draft has much more positive outcomes than other alternatives; with respect to primary energy and impact on the environment. However, the final draft has higher purchase costs and its financial and operational economy is extremely dependent on the prices of electric power.

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.

In this project a steady-state building load for Constant Volume Terminal Reheat (CVTR), Dual Duct Constant Volume (DDCV) and Dual Duct Variable Air Volume (DDVAV) systems for the Zachry Engineering Building has been modeled. First, the thermal resistance values of the building structure have been calculated. After applying some assumptions, building characteristics were determined and building loads were calculated using the diversified loads calculation method. By having the daily data for six months for the Zachry building, the input to the CVTR, DDCV and DDVAV Microsoft Excel code were prepared for starting the simulation. The air handling units for the Zachry building are Dual Duct Variable Air Volume (DDVAV) systems. The calibration procedure has been used to compare the calibration signatures with characteristic signatures in order to determine which input variables need to be changed to achieve proper calibration. Calibration signatures are the difference between measured energy consumption and simulated energy consumption as a function of temperature. Characteristic signatures are the energy consumption as a function of temperature obtained by changing the value of input variables of the system. The base simulated model of the DDVAV system has been changed according to the characteristic signatures of the building and adjusted to get the closest result to the measured data. The simulation method for calibration could be used for energy audits, improving energy efficiency, and fault detection. In the base model of DDVAV, without any changes in the input, the chilled water consumption had an Root Mean Square Error (RMSE) of 56.705577 MMBtu/day and an Mean Bias Error (MBE) of 45.763256 MMBtu/day while hot water consumption had an RMSE of 1.9072574 MMBtu/day and an MBE of 45.763256 MMBtu/day. In the calibration process, system parameters such as zone temperature, cooling coil temperature, minimum supply air and minimum outdoor air have been changed. The decisions for varying the parameters were based on the characteristic signatures provided in the project. After applying changes to the system parameters, RMSE and MBE for both hot and cold water consumption were significantly reduced. After changes were applied, chilled water consumption had an RMSE of 12.749868 MMBtu/day and an MBE of 3.423188 MMBtu/day, and hot water consumption had an RMSE of 1.6790 MMBtu/day and an MBE 0.12513 of MMBtu/day.

La pollution de l'air est l'un des principaux problèmes de santé publique de notre siècle et surtout de l'air intérieur alors que nous passons environ 90% de notre temps dans des environnements fermés. Parmi les polluants les bioaérosols ont été peu étudiés. Cependant des études épidémiologiques ont déjà montré une relation entre les bioaérosols et la santé. Le but de cette thèse est d’étudier les virus respiratoires dans les milieux clos via les systèmes de ventilation. A l’issue d’un état de l’art des polluants de l’air, il est important de définir ceux nécessitant d’être traités, les systèmes de ventilation, les procédés de filtration par médias fibreux et les procédés de traitement pouvant être mis en oeuvre. Les effets des bioaérosols viraux dans les environnements intérieurs sur la santé publique ont été discutés dans une revue bibliographique. Une méthodologie a été mise en oeuvre pour étudier le comportement des virus dans une centrale de traitement de l’air (CTA). Les virus respiratoires, mengovirus (virus nu à ARN de la même famille que les rhinovirus responsables du rhume) et adénovirus (virus respiratoire nu à ADN), ont été choisis et étudiés dans un système expérimental miniature représentatif des systèmes de traitement d’air. La performance de filtration d’un filtre de CTA vis-à-vis des aérosols viraux a été évaluée avec une validation du système expérimental utilisé. Cette étude a montré la capacité des virus de passer à travers le filtre tout en restant infectieux. Peu de littérature existant sur le sujet, ce projet a permis d’ajouter de nouvelles données pertinentes quant à la persistance des virus respiratoires dans l’air intérieur et plus précisément au niveau des filtres dans les centrales de traitement d’air. / Air pollution is one of the major public health problems of our century and especially of indoor air as we spend about 90% of our time in closed environments. Among pollutants bioaerosols have been poorly studied. However, epidemiological studies have already shown a relationship between bioaerosols and human health. The aim of this PhD work is to learn about respiratory viruses in closed environments via ventilation systems in order to study indoor air quality. At the end of state of the art of air pollutants, it is important to define those present in the air that need to be treated, ventilation systems, filtration processes by fibrous media and the processing methods being able to be implemented. The effects of viral bioaerosols on public health in indoor environments were discussed and drafted in a bibliographic review. The methodology of the study was to assess the fate of respiratory viruses, mengoviruses and adenoviruses, in a miniature experimental system similar to air treatment systems used in closed environments. The experimental system used was validated and the filter performance against viral aerosols was investigated. This study presented originality for the characterization and the fate of two non-enveloped respiratory viruses, mengovirus (RNA) and adenovirus (DNA), in indoor environments and their fate on fiber glass filter. This study showed the ability of viruses to pass through the filter and to remain infectious upstream and downstream the filter. There is scarce literature on this subject, and this project allowed us to add new relevant data on the persistence of respiratory viruses in indoor air and more precisely at the level of filters in air handling units.

This thesis deals with the relationship between HVAC systems and internal microclimate of buildings. The work discusses briefly about different components which are formulating internal microclimate. More details are then focused on the issue of microbial microclimate.

This master's thesis explores the role of bespoke air handling units in enhancing energy efficiency in existing buildings. The context for the study is set against the backdrop of global initiatives, including the United Nations' Sustainable Development Goals, specifically Goal 7, which emphasizes the need to improve energy efficiency to combat climate change. The significance of enhancing energy efficiency is well-established, evident both at the EU level and in national policies and regulations. Buildings represent a significant portion of the energy utilization puzzle, with substantial potential for enhancing energy efficiency, although it is often underutilized. One of the contributing factors to inefficiency is outdated ventilation systems, which lead to high thermal losses. This challenge can be addressed by retrofitting these systems with modern, efficient air handling units, thus contributing to energy conservation and cost savings. This study focuses on the adoption of bespoke air handling units adjusted to the site and capable of accommodating constraints related to factors such as space limitations in machine rooms, existing ductwork layouts, and the location of shafts. The primary goal is to empower engineers to move beyond conventional approaches, enabling them to optimize technology choices based on local conditions, specific system performance requirements, and the economic viability of each project. The aim of this study is twofold: first, to develop a methodology for designing bespoke air handling units; and second, to demonstrate the practical application of this methodology in the context of two distinct renovation projects. In line with the aim of the thesis, a design methodology for site-tailored units equipped with a two stage flat crossflow heat exchanger and an indirect evaporative cooling system was developed. The methodology delves into different aspects of data analysis, 3D modeling, and the conduct of performance calculations.The established methodology was applied in two reconstruction projects in central Stockholm, where bespoke air handling units were designed in compliance with provided technical specifications. In both scenarios, a viable option emerged for accommodating a tailored unit within the technical room situated on the first floor. For both units, the energy performance metrics signify a notable achievement in terms of heat recovery efficiency, coupled with relatively modest requirements for heating and cooling power capacity from the combined heating and cooling aircoil. However, the calculated maximum specific fan power for a single unit with heat recovery exceeded the stipulated value specified in the technical specifications, which was accepted by the client. The results of the study included air handling unit product drawings, ventilation blueprints of the technical room with the integrated air handling unit, component specifications, unit flowcharts, performance calculations, and control operating pictures. The results of this work indicate that the improvement of the building's energy efficiency is rendered feasible through the installation of bespoke air handling units in the studied reconstruction projects. / Se filen