Ventilation systems are closely connected to indoor environment. In industrial spaces it has a major impact due to air quality and thermal comfort requirements, which leads into health and economy improvements. Confluent jets ventilation system has been assess in Söderhamn Eriksson, a machinery company located in Mariannelund, Sweden, since it has been proved as the best ventilation performance. Moreover this system is worthy for both heating and cooling purposes, although just heating case will be developed in this thesis. By means of modelling software such as Gambit and Airpak, the company’s case could have been analyzed via Computational Fluid Dynamics (CFD) software, i.e. Fluent. The analyzed models were accepted after a thorough study of meshing parameters, bearing in mind computational limitations. Every temperature data gathered from simulation results has been verified with infrared camera figures taken at the company, thus contributing to reach reliable conclusions. As it is inferred from previous papers and empiric theory, the flow field observed is also justified. Then, thermal comfort and air quality analysis relies on consistent facts. It has been found that current ventilation at the company is slightly misadjusted, since supplied air’s temperature and velocity are slightly off point. Therefore, it is recommended to reduce these values to reach better working environment.

In recent years, many strides have been achieved in the area of Wireless Sensor Networks (WSNs), which is leading to constant innovations in the types of applications that WSNs can support. Much advancement has also been achieved in the area of smart homes, enabling its occupants to manually and easily control their utility expenses. In this thesis, both areas of research will be colluded for a simple, yet critical application: efficient and economical comfort control in smart residential spaces. The goal is to design a central, modular energy consumption control system for residential spaces, which manages energy consumption in all aspects of a typical residence. This thesis is concerned with two facets of energy consumption in residences. The first facet is concerned with controlling when the heating, ventilating, and air conditioning unit (HVAC) operates for each room separately. This is in contrast to a typical HVAC system where comfort is provided across the floor as a whole. The second facet is concerned with controlling the lighting in each room so as to not exceed a certain input value. The communication network that supports the realization of these coveted goals is based on Zigbee interconnected sensor nodes which pour data unto a smart thermostat which does all the required calculations and activates the modules required for comfort control and energy management, if needed. A Java-based discrete event simulator is then written up to simulate a floor of a typical Canadian single-family dwelling. The simulation assumes error-less communication and proceeds to record certain room variables and the ongoing cost of operation periodically. These results from the simulator are compared to the results of the well known simulator, created by DesignBuilder, which describes typical home conditions. The conclusion from this analysis is that the Comfort Control and Energy Management Algorithms (CEMA) are feasible, and that their implementation incurs significant monetary savings.

In this thesis, several possible liquid desiccants (aqueous solutions of LiCl, LiBr, MgCl2 and CaCl2) are investigated to find the most appropriate working fluid to be used in a run-around membrane energy exchanger (RAMEE). The liquid desiccant is one of the main components of the RAMEE and indirectly conditions the outdoor ventilation air by using the energy of the exhaust air, significantly reducing the building energy consumption.<p> Numerical simulations, in this thesis, show that the total effectiveness of the RAMEE changes less than 0.5% when different salt solutions are used. However, the capital and operational costs of the RAMEE are significantly different for different desiccants. MgCl2 is the most inexpensive among the selected salt solutions and is followed by CaCl2, LiBr and LiCl. The price of a LiCl solution in the RAMEE is almost 20 times more than the price of MgCl2 solution. Different thermo-physical properties of the salt solutions result in different pumping energy consumptions for each specific salt solution. For example, the pumping energy consumption for a MgCl2 solution is 3.5 times more than for a LiBr solution in the RAMEE. The change in the volume of the liquid desiccant throughout a year is another characteristic which depends on the thermo-physical properties of the salt solution. Solutions with larger volume expansion require larger storage tanks and will experience longer transient delays. The difference between the volume expansions of different salt solutions is less than 5% of the total solution volume. MgCl2 solution expands more than 17% throughout a yearly operation of the system in Saskatoon.<p> Crystallization of the salt solution is another important parameter in the selection of the liquid desiccant. Simulations show that, for a specific indoor and outdoor operating condition the risk of crystallization is greatest for MgCl2, followed by CaCl2, LiCl and LiBr. The risk increases as the supply or exhaust airstreams become dryer. For a cross flow RAMEE with a total effectiveness of 55% (NTU=10 and Cr*=3) operating in a building with indoor RH of 50%, the critical outdoor humidity below which crystallization will begin to occur is 28% RH for MgCl2, 20% for CaCl2 and 0%RH for LiCl and LiBr. According to the simulations, all four investigated salt solutions can be used in North America (except the states of Nevada, Arizona, New Mexico and parts of Texas) with no risk of crystallization when the indoor humidity is 50% RH. However, with indoor humidity of 30% MgCl2 and CaCl2 solutions will have risk of crystallization for a large number of hours in a year in most of the central western United States. A mixture of 50% LiCl and 50% MgCl2 solution is suggested to be used when the cost-effective MgCl2 solution cannot be used due to crystallization issues. The price of this newly suggested mixture is 30% less than that of a pure LiCl solution and can be used in all North American climates with very small risk of crystallization.

In recent years, many strides have been achieved in the area of Wireless Sensor Networks (WSNs), which is leading to constant innovations in the types of applications that WSNs can support. Much advancement has also been achieved in the area of smart homes, enabling its occupants to manually and easily control their utility expenses. In this thesis, both areas of research will be colluded for a simple, yet critical application: efficient and economical comfort control in smart residential spaces. The goal is to design a central, modular energy consumption control system for residential spaces, which manages energy consumption in all aspects of a typical residence. This thesis is concerned with two facets of energy consumption in residences. The first facet is concerned with controlling when the heating, ventilating, and air conditioning unit (HVAC) operates for each room separately. This is in contrast to a typical HVAC system where comfort is provided across the floor as a whole. The second facet is concerned with controlling the lighting in each room so as to not exceed a certain input value. The communication network that supports the realization of these coveted goals is based on Zigbee interconnected sensor nodes which pour data unto a smart thermostat which does all the required calculations and activates the modules required for comfort control and energy management, if needed. A Java-based discrete event simulator is then written up to simulate a floor of a typical Canadian single-family dwelling. The simulation assumes error-less communication and proceeds to record certain room variables and the ongoing cost of operation periodically. These results from the simulator are compared to the results of the well known simulator, created by DesignBuilder, which describes typical home conditions. The conclusion from this analysis is that the Comfort Control and Energy Management Algorithms (CEMA) are feasible, and that their implementation incurs significant monetary savings.

In this thesis, several possible liquid desiccants (aqueous solutions of LiCl, LiBr, MgCl2 and CaCl2) are investigated to find the most appropriate working fluid to be used in a run-around membrane energy exchanger (RAMEE). The liquid desiccant is one of the main components of the RAMEE and indirectly conditions the outdoor ventilation air by using the energy of the exhaust air, significantly reducing the building energy consumption.<p> Numerical simulations, in this thesis, show that the total effectiveness of the RAMEE changes less than 0.5% when different salt solutions are used. However, the capital and operational costs of the RAMEE are significantly different for different desiccants. MgCl2 is the most inexpensive among the selected salt solutions and is followed by CaCl2, LiBr and LiCl. The price of a LiCl solution in the RAMEE is almost 20 times more than the price of MgCl2 solution. Different thermo-physical properties of the salt solutions result in different pumping energy consumptions for each specific salt solution. For example, the pumping energy consumption for a MgCl2 solution is 3.5 times more than for a LiBr solution in the RAMEE. The change in the volume of the liquid desiccant throughout a year is another characteristic which depends on the thermo-physical properties of the salt solution. Solutions with larger volume expansion require larger storage tanks and will experience longer transient delays. The difference between the volume expansions of different salt solutions is less than 5% of the total solution volume. MgCl2 solution expands more than 17% throughout a yearly operation of the system in Saskatoon.<p> Crystallization of the salt solution is another important parameter in the selection of the liquid desiccant. Simulations show that, for a specific indoor and outdoor operating condition the risk of crystallization is greatest for MgCl2, followed by CaCl2, LiCl and LiBr. The risk increases as the supply or exhaust airstreams become dryer. For a cross flow RAMEE with a total effectiveness of 55% (NTU=10 and Cr*=3) operating in a building with indoor RH of 50%, the critical outdoor humidity below which crystallization will begin to occur is 28% RH for MgCl2, 20% for CaCl2 and 0%RH for LiCl and LiBr. According to the simulations, all four investigated salt solutions can be used in North America (except the states of Nevada, Arizona, New Mexico and parts of Texas) with no risk of crystallization when the indoor humidity is 50% RH. However, with indoor humidity of 30% MgCl2 and CaCl2 solutions will have risk of crystallization for a large number of hours in a year in most of the central western United States. A mixture of 50% LiCl and 50% MgCl2 solution is suggested to be used when the cost-effective MgCl2 solution cannot be used due to crystallization issues. The price of this newly suggested mixture is 30% less than that of a pure LiCl solution and can be used in all North American climates with very small risk of crystallization.

This dissertation provides a detailed description of the research work completed on fin staged heat exchangers. The effects of staging fin on the frosting performance of heat pump evaporators and the whole heat pump system have been studied experimentally and theoretically. Frost degrades the performance of fin-and-tube outdoor coils as well as the whole heat pump system. The objective of the experimental part of this study was to investigate the effects of the staging fin on the frost/defrost performance of heat pump outdoor coils under different operating conditions. To accomplish this objective, a series of frosting tests was conducted on an off-the-shelf heat pump system with five (three two-row and two three-row) evaporators over a range of outdoor temperatures and humidities and a range of airflow rates typical of those found in residential sized heat pumps. Performances of the heat pump unit with baseline or fin staged outdoor coils at either frosting or steady-state test conditions are compared and analyzed. Experimental data showed that for a given tworow heat pump outdoor coil operating at the standard ANSI/ASHRAE 35 °F (1.7 °C) frosting conditions, fin staging increased cycle time and COP. There was a small decrease in peak capacity at lower initial airflow rates. At a lower temperature of 28 °F (2.2 °C), cycle time continued to be enhanced with fin staging, and cyclic COP was within 5% of the base case when fin staging was used. In the second step of this work, an analytical model to simulate the performance of both the baseline and fin staged heat pump coils under frosting conditions was developed based on fundamental heat and mass transfer principles. The transient performance of the frosted evaporator was analyzed with the quasi-steady state approach. The section-by-section evaluation scheme was combined with the tubeby- tube approach to model the mass transfer process in the frost formation module. The two-dimensional fin surface was divided into a number of parallel non-overlapping sections. Each of the sections was the calculation unit for the mass transfer. Methods for calculating the airside heat transfer coefficient and friction factor were developed and applied to the simulation model of the fin staged coil. To verify the validity of the frosted evaporator model, the frosting performance of three two-row coils at the same test conditions was simulated and compared with experimental data. The frosted evaporator model appeared to provide satisfactory simulation of the fin-and-tube heat exchanger during the frost buildup process. Comparisons with the test data indicated that the model could capture the trends of the coil capacity, pressure drop, airflow and frost growth. The model also provided a variety of other simulation results including frost mass accumulation, air velocity inside coil, air and refrigerant outlet state, and so on. Overall, the numerical results were in reasonable agreement with the test data under different frosting operation conditions.

Empirical models of airflow output and power consumption were developed for series and parallel fan powered variable air volume terminal units at typical design pressure conditions. A testing procedure and experimental setup were developed to test sets of terminal units from three different manufacturers. Each set consisted of two series and two parallel units, each with 8 in. (203 mm) and 12 in. (304 mm) primary air inlets, for a total of four units in each set. Generalized models were developed for the series and parallel units, with coefficients varying by size and manufacturer. Statistical modeling utilized SAS software (2002). Fan power and airflow data were collected at downstream static pressures over a range from 0.1 to 0.5 in. w.g. (25 to 125 Pa) for the parallel terminal units. Downstream static pressure was held constant at 0.25 in. w.g. (62 Pa) for the series units. Upstream static pressures of all variable air volume (VAV) terminal units ranged from 0.1 to 2.0 in. w.g. (25 to 498 Pa). Data were collected at four different primary air damper positions. Data were also collected at four different terminal unit fan speeds, controlled by a silicon controlled rectifier (SCR). The models utilized the RMS voltage entering the terminal unit fan, the 'rake' sensor velocity pressure, and the downstream static pressure. In addition to the terminal unit airflow and power models, a model was developed to quantify air leakage in parallel terminal units, when the unit fan was off. In all but two of the VAV terminal units, the resulting models of airflow and power had R2 values greater than 0.90. In the two exceptions, there appeared to be manufacturing defects: either excessive air leakage or a faulty SCR that limited the effectiveness of the airflow and power models to capture the variation in the data.

Due to lacking of natural resources, the major energy utilized in Taiwan are mostly imported, including oil (50.9%), Coal (32.3%), and natural gas (8.1%), nuclear (7.3%) and hydraulic power (1.4%). Therefore, energy saving strategies have become a global trend and needs immediate action so that CO2 emission can be reduced. To coup with the Kyoto protocol, building energy conservation has been deemed as a policy of no regret and aiming at 20% savings in the whole nation. In this research, building energy conservation strategies, especially on HVAC systems which have been widely adapted in Taiwan will be analyzed and validated with full-scale experimental results. Efforts will be especially focused on commercial and residential buildings, so that their energy savings effect can be analyzed quantitatively.

This study aims at a preliminary characterization of system operation uncertainty. It bases this on an analysis of the energy consumption of 6 existing buildings on the Georgia Tech campus. The analysis is speculative in nature.

The primary purpose of the current research was to implement a numerical model to investigate the interactions between the energy consumption in Heating, Ventilating, and Air Conditioning (HVAC) systems and occupants’ thermal comfort in commercial buildings. A numerical model was developed to perform a thermal analysis of a single zone and simultaneously investigate its occupants’ thermal sensations as a non-linear function of the thermal environmental (i.e. temperature, thermal radiation, humidity, and air speed) and personal factors (i.e. activity and clothing). The zone thermal analyses and thermal comfort calculations were carried out by applying the heat balance method and current thermal comfort standard (ASHRAE STANDARD 55-2004) respectively. The model was then validated and applied on a single generic zone, representing the perimeter office spaces of the Centre for Interactive Research on Sustainability (CIRS), to investigate the impacts of variation in occupants’ behaviors, building’s envelope, HVAC system, and climate on both energy consumption and thermal comfort. Regarding the large number of parameters involved, the initial summer and winter screening analyses were carried out to determine the measures that their impacts on the energy and/or thermal comfort were most significant. These analyses showed that, without any incremental cost, the energy consumption in both new and existing buildings may significantly be reduced with a broader range of setpoints, adaptive clothing for the occupants, and higher air exchange rate over the cooling season. The effects of these measures as well as their combination on the zone thermal performance were then studied in more detail with the whole year analyses. These analyses suggest that with the modest increase in the averaged occupants’ thermal dissatisfaction, the combination scenario can notably reduce the total annual energy consumption of the baseline zone. Considering the global warming and the life of a building, the impacts of climate change on the whole year modeling results were also investigated for the year 2050. According to these analyses, global warming reduced the energy consumption for both the baseline and combination scenario, thanks to the moderate and cold climate of Vancouver.