With the need for excellent living standards to escalate day by day, the need to breathe good quality air remains of paramount importance for a prosperous, happy life. The indoor air quality picture is improving decade by decade. However, the importance of maintaining good indoor air quality remains unsatisfactory. Indoor air quality is one of the world’s most significant environmental problems. Statistics states that as of 2017, approximately 1.6 million premature deaths are caused by bad indoor air quality. The majority of these deaths result from the presence of Volatile Organic compounds in the air. VOCs are the common pollutants that are found indoors, which are not only toxic but also dangerous to health on long exposures. Even though several norms are put in place, why is the picture still persistent even after many technological advancements in the industry? This notion of this idea inspired the authors to conduct the current thesis. The thesis is based on a case study at a Swedish Air-cleantech company, Company-X, that developed efficient air filtration technologies to eliminate VOCs from the indoor air. However, for efficient diffusion of the technology, studying the market is of utmost importance. For this, the study is done by qualitative interviewing of professionals from the Swedish air filtration market. The interactions helped the authors to comprehend the more in-depth picture of influencing facets in persistent VOC issues in the indoor airs. Secondly,the meetings guided the authors with the industry choice for efficient technologies to eliminate VOCs from the indoor air. The collected data led to the conclusions that, various actors like awareness and buying decision factors, technologies are involved for VOCs still being a persistent issue in indoor airs. The industry’s awareness regarding Volatile Organic Compounds has been mediocre, and the significant factor for the buying decision is the price. Speaking of the technology, it has been reckoned that Activated Carbon filters are the best and economically efficient technology to eliminated VOCs from the air.

The diploma thesis deals with automated measurement of humidity and CO2 concentration inside buildings. Results of this measurement form the input parameters for the effective management of technologies reducing the energy performance of buildings. In the introduction, the issue of indoor air quality of buildings and indicators characterizing this quality are approached. The technical part of the thesis consists of making a measuring device which contains two prototype sensors provided by Teco Inc. with online access to measured data. The measurement of relative humidity, CO2 concentration and temperature in the interior of the building with the made device is compared with commercially available devices for measuring selected parameters. For unambiguous interpretation of online data, the virtual machine with an online database is configured for the created measuring device. The possibilities of using the prepared measuring device to achieve a reduction in the energy performance of buildings are discussed in the final part.

The work deals with indoor air quality and ventilation control based on indoor air quality. Based on the analysis of the concentration of CO2, heat and moisture gains can suggest the optimal way to reduce excessive ventilation

The thesis analyses heat loss caused by ventilation for various volumes of ventilated air. Number of model cases were analyzed (class room, fit center, auditorium in the cinema and an apartment). Every scenario was analyzed with the heat recuperation and without it. Annual energetic balance and influence of heat recuperation was evaluated for every model case thereafter. Simulations of ventilation energy consumption were carried out in the TRNSYS 16 program.

This thesis deals with the influence of the location of exhaust outlets on the air quality. The study examines the performance of the hybrid ventilation system installed in an experimental house. The central point of this work is a numerical model of a bedroom with heat and carbon dioxide sources. The temperature, speed and concentration fields have been solved for, from which further quantities of thermal comfort PMV, PPD and DR were evaluated. Finally, the impact of changes in the quality of the microclimate using these quantities and in the energy efficiency ventilation is assessed.

A real-world study was undertaken of the indoor air quality in a recently-built single family home in central Sweden, to establish whether demand controlled ventilation provided superior interior conditions, when compared with other air supply strategies, including the standard used by the Swedish buildings regulator. The property was highly airtight, with ventilation achieved using a forced exhaust system. Extraction was possible from all rooms of the house, and using a Renson Healthbox air handling unit, the rates of air flow from each room could be adjusted either according to a time schedule, or under demand control according to the unit’s sensing of the air quality in individual rooms. Five ventilation modes were evaluated, each for a period of 24 hours. Occupancy of the house was standardised, with test participants. Two separate air quality monitors were deployed to verify whether measurements made at the air handling unit were representative of the conditions that occupants experienced. Key measurements were the stable level of carbon dioxide overnight in an occupied double bedroom and the time taken for that room to refresh to background CO2 level the following day. The time taken for a kitchen/living room to similarly refresh was also examined. The study found that demand controlled ventilation achieved indoor air quality – assessed on carbon dioxide concentration – comparable with rates of fixed ventilation far greater than the regulated standard. In doing so, the air volume exchanged over a representative day was 33 % less than that standard, providing for significant energy savings. The parallel monitoring of air quality inside the room and via the air exhaust duct showed noticeable variation, but indicated the air handling unit under demand control would never ventilate insufficiently, based on its internal CO2 sensors.

This study has been motivated by an understanding of the twin needs to reduce carbon dioxide emissions and increase the access to have complete control of the ventilation system available in the buildings. In consideration of the increasing utilization of fossil fuels, there is an extensive threat of increased global warming conditions associated. To ensure sustainable development, improvement of social welfare and wealth creation, energy is an essential factor. The consumption of electricity and energy delivered per floor area in Sweden has been considerably rising since 2014. The aim of this study is twofold where the authors have mapped and defined the specific customer needs for choosing an “add-on energy optimization module” for the existing HVAC systems in Sweden’s commercial market. Secondly, the study has also focussed to identify the acceptance of the complementary good technology from the perspective of a customer’s experience of value creation. It is a case study carried out in collaboration with a Swedish cleantech company, that will be named “Company-X” in the further part of the study. This company utilises a part of space technology to secure a healthy indoor air climate and at the same time save energy in buildings. The thesis has been carried out qualitatively. Since there is a preunderstanding of this theory where an abductive approach with semi-structured interviews has been followed to perceive the current market situation. The study further underlines the importance and need of making investments for a cleaning module combined with an optimization algorithm which can be easily mounted on current ventilation systems like Lego pieces. Under this module, the air quality is monitored, and the system adapts to current conditions concerning time. The results designate that it is possible to maintain a predefined indoor air quality to the lowest possible energy consumption by real-time monitoring with this cleaning module at facilities that are equipped with single or multiple-split HVAC systems. The best results towards attaining greater energy savings can be obtained from the association of Building energy management system and Air-handling unit with this cleaning module.

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Nowadays individuals spend more than 85% of their total time in indoor environments, mainly at home and work. Thereby, the quality of the indoor environment plays a substantial role in human health and wellness. The four basic factors that define the perception of the indoor environment, through the senses, are the thermal comfort, the indoor air quality, the acoustical quality and the visual or lighting quality. A standard level of the above factors is ensured by the building envelope and the services systems. At the same time, the bearing structure provides the necessary resistance and durability to the construction in order to sustain the various loads without breaking down. Inevitably, over the years, all structures’ robustness declines and their functionality state degrades. For that reason, intensive provision should be given to assure the users’ safety and well-being. The objective of this study is to assess the current indoor air quality, the thermal comfort and the damages at four publicly owned buildings located in Athens, Greece. The evaluation was done through the facilities management contribution, a questionnaire survey and a technical visit – inspection where measurements were taken. Special focus was also put on the Sick Building Syndrome (SBS) and its effects. The results indicated that at 3 out of 4 buildings mainly suffer from unpleasant odors and lack of fresh air intake. Therefore, the installation of mechanical ventilation systems (air handling units, outdoor air processing units) combined with an effective air distribution system (confluent jet ventilation system) is suggested. Substantial building damages were detected at the cultural center (floorings, door/window openings, fungi) and specific proposals for restoration are made. Despite the existence of indicators of an unhealthy indoor environment, a direct correlation between the exposure to various pollutants and the SBS symptoms, cannot be established. The optimization of the research methodologies and the institution of new building design protocols is essential in order to overcome the SBS effects. On the whole, the questionnaire achieved to fulfil the objectives of the survey. It was comprehensible by the respondents while the outcome of the questionnaire and the inspection were consistent to each other. The questionnaire and the checklists are practical tools that could be used as a guide for future investigation in similar fields. Except for technical surveys and questionnaires, many suggestions for future maintenance of the buildings are provided aiming to retain their functionality. These proposals concern the services systems, the building envelope as well as the bearing structure of the buildings.

Acute indoor concentrations of benzene and ethanol were evaluated in the California Polytechnic State University San Luis Obispo’s pilot winery workroom. Air samples were collected during four different wine-making activities: fermentation, fermentation with Brix content testing, post-alcoholic fermentation pressing, and storage/finishing. Average workroom benzene concentrations ranged from 0.05 to 0.12 mg/m3. Ethanol concentrations in the winery workroom varied with the activity, ranging from 0.9 to 12 mg/m3. Pressing and fermentation with Brix content testing both led to higher indoor ethanol concentrations than fermentation without Brix content testing and storage/finishing. Tracer gas decay air exchange tests were conducted to determine the air exchange rate of the winery workroom. A single-space mass-balance model was used to estimate the air exchange rate for the entire workroom. The calculated air exchange rates were correlated with wind speeds and wind direction to create a linear model estimating air exchange rates based on wind speed. These air exchange rates and the indoor concentrations of ethanol were used with the single-space mass-balance model to calculate an ethanol emission rate for each activity. Total estimated ethanol emissions for the four activities were 3.1 lbs. ethanol per 1000 gallons of wine produced.