Engineering Commons^™

Experiences And Learning Outcomes Of Using Virtual Reality In Building Services Engineering Education, Juho Posio, Petteri Maljamäki, Marko Haavikko, Tauno Tepsa, Heli Väätäjä

Research Papers

Virtual Reality (VR) is a promising learning environment in vocational and higher education as it enables learning by doing. We developed a digital twin (DT) for learning the most common maintenance procedures of an air-to-water heat pump using game engine technology, targeted for students and professionals in the building services engineering industry. 22 HVAC (heating, ventilation and air conditioning) students participated in a user study to evaluate their experience with the DT, their usage preferences, and learning outcomes. Results of an online posttest questionnaire show that participants found the use of the DT easy and useful for learning maintenance procedures, …

Changing Climates And Extreme Weather For Minnesota, Patrick A. Tebbe

Mechanical and Civil Engineering Department Publications

Climate change is impacting the design, prediction, and operation of HVAC systems for the built environment, and will continue to do so for the foreseeable future. This presentation reviews climate predictions for the upper Midwest and how they will affect the HVAC industry. Topics such as changing design conditions, extreme weather impact, and increased electrification will be addressed.

Controlling Sars Related Illnesses In The Indoor Environment Using Hvac Ventilation Techniques, Natalie Mansson

Construction Management Theses

The COVID-19 pandemic has brought on a need for better ventilation systems due to the deadly spreading of the SARS-CoV and SARS-CoV-2 illness through the air. As the positivity rate increases sharply, this study is pertinent in the fight against the virus. The implementation of MERV filters and ventilation rates while also understanding respiratory droplets and how they move through the air is an important part of understanding airborne transmission. Much research has been done on MERV filtration and respiratory droplets and their traveling methods in the air, and this research aims to find the commonalities between prior research, and …

Covid-19 Public Transportation Air Circulation And Virus Mitigation Study, Aly Tawfik, Deify Law, Juris Grasis, Joseph Oldham, Moe Salem

Mineta Transportation Institute

COVID-19 may have forever changed our world. Given the limited space and air circulation, potential infections on public transportation could be concerningly high. Accordingly, this study has two objectives: (1) to understand air circulation patterns inside the cabins of buses; and (2) to test the impact of different technologies in mitigating viruses from the air and on surfaces inside bus cabins. For the first objective, different devices, metrics and experiments (including colored smoke; videotaping; anemometers; pressure differentials; particle counts; and 3D numerical simulation models) were utilized and implemented to understand and quantify air circulation inside different buses, with different characteristics, …

Active Membrane Energy Exchanger For Air Cooling And Dehumidification, Songhao Wu, Andrew Fix, David M. Warsinger, James E. Braun

Discovery Undergraduate Interdisciplinary Research Internship

Heating, ventilation and air conditioning (HVAC) equipment consume 35% of total building energy use in the US, among which a large share is used for cooling and dehumidification. The majority of air dehumidification systems take the conventional approach of moisture condensation removal. It requires air to be cooled below its dew point temperature and is an energy-intensive process, especially for areas with hot and humid climates. Vapor selective membrane systems are promising alternatives for air dehumidification as they do not require cooling energy for latent (humidity) heat removal. It allows water vapor transport through the membrane while blocking air. Previous …

Artificial Intelligence Method For The Forecast And Separation Of Total And Hvac Loads With Application To Energy Management Of Smart And Nze Homes, Rosemary E. Alden, Huangjie Gong, Evan S. Jones, Cristinel Ababei, Dan M. Ionel

Electrical and Computer Engineering Faculty Publications

Separating the HVAC energy use from the total residential load can be used to improve energy usage monitoring and to enhance the house energy management systems (HEMS) for existing houses that do not have dedicated HVAC circuits. In this paper, a novel method is proposed to separate the HVAC dominant load component from the house load. The proposed method utilizes deep learning techniques and the physical relationship between HVAC energy use and weather. It employs novel long short-term memory (LSTM) encoder-decoder machine learning (ML) models, which are developed based on future weather data input in place of weather forecasts. In …

Investigation Of The Prevalence Of Faults In The Heating, Ventilation, And Air-Conditioning Systems Of Commercial Buildings, Amir Ebrahimifakhar

Durham School of Architectural Engineering and Construction: Dissertations, Thesis, and Student Research

This dissertation describes a large-scale investigation of heating, ventilation, and air-conditioning (HVAC) fault prevalence in commercial buildings in the United States. A multi-year dataset with 36,556 pieces of HVAC equipment including air handling units (AHUs), air terminal units (ATUs), and packaged rooftop units (RTUs) was analyzed to determine values for several HVAC fault prevalence metrics. The primary source of data for this study comes from three commercial fault detection and diagnostics (FDD) providers. Since each FDD provider uses different terms to refer to the same fault in an HVAC system, a mapping function was created for each FDD provider’s dataset, …

Virtual Power Plant Control For Large Residential Communities Using Hvac Systems For Energy Storage, Huangjie Gong, Evan S. Jones, Rosemary E. Alden, Andrew G. Frye, Donald G. Colliver, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Heating, ventilation, and air-conditioning (HVAC) systems use the most electricity of any household appliance in residential communities. HVAC system modeling facilitates the study of demand response (DR) at both the residential and power system levels. In this article, the equivalent thermal model of a reference house is proposed. Parameters for the reference house were determined based on the systematic study of experimental data obtained from fully instrumented field demonstrators. Energy storage capacity of HVAC systems is calculated and an equivalent state-of-charge is defined. The uniformity between HVAC systems and battery energy storage system is demonstrated by DR control. The aggregated …

Generalized Energy Storage Model-In-The-Loop Suitable For Energy Star And Cta-2045 Control Types, Huangjie Gong, Evan S. Jones, A. H. M. Jakaria, Aminul Huque, Ajit Renjit, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

The paper proposes a generalized energy storage (GES) model for battery energy storage systems (BESS), electric water heaters (EWH) and heating, ventilation, and air-conditioning (HVAC) systems. The analogies, including state of charge versus water temperature differential, are identified and explained, and models-in-the-loop (MIL) are introduced, which are compatible with the Energy Star and CTA-2045 general specifications and command types. Emphasis is placed on the proposed EWH model as it needfully fulfills a gap in present literature. The corresponding MIL has been implemented in the DER integration testbed, which was originally developed by EPRI, and satisfactorily validated against experimental results. A …

Power Factor And Reactive Power In Us Residences – Survey And Energyplus Modeling, Hope C. Anderson, Abdullah Al Hadi, Evan S. Jones, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Electric power systems are experiencing a growing number of electronic loads in the residential sector as modern appliance technology progresses, and it has become increasingly more important to consider the total power factor (PF) of residential communities. This paper provides a survey based on literature and publicly available information of typical appliance PF values and effects at the residential level as well as a discussion on appliance energy use and corresponding operation schedules. A procedure for the calculation of equivalent PF is proposed and exemplified with minutely experimental data at 15-minute and hourly time intervals, which correspond to smart metering …

Artificial Intelligence-Based Short-Term Electric Load Forecasts For Experimental Smart Homes Including Hvac And Pv Components, Rosemary E. Alden, Cristinel Ababei, Dan M. Ionel

Power and Energy Institute of Kentucky Presentations

Problem Formulation

• To predict electric load of the total average power as well as individual components for two residencies from experimental data
• Individual residential forecasting is difficult due to high variability of appliance usage and random human behavior influences
• Separate the HVAC load from total load as a desired profile using weather relationship and minimum HVAC load at night
• Data driven approach to reduce the amount of information about the home required

Lab Home Testing Of Residential Isolation Space Control To Minimize Infectious Disease Transmission In Existing Single-Family Homes -- Fact Sheet, Florida Solar Energy Center, Tanvir Khan

FSEC Energy Research Center®

The FSEC Energy Research Center at the University of Central Florida performed research to test the effectiveness of interventions to isolate an ill person recovering from a contagious disease in a single-family home from the rest of the occupants in the home. Focus was placed on interventions requiring minor cost and effort on the part of the occupants.

DOE/GO-102021-5537, https://www.nrel.gov/docs/fy21osti/79519.pdf

Lab Home Testing Of Residential Isolation Space Control To Minimize Infectious Disease Transmission In Existing Single-Family Homes, Florida Solar Energy Center, Tanvir Khan

FSEC Energy Research Center®

Existing evidence strongly suggests that viral infectious diseases can be transmitted via an airborne route across distances in indoor environments. Accordingly, the risk of airborne transmission within homes should be managed. The public health emergency associated with SARS-CoV-2 makes controlling airborne transmission of respired viruses in indoor environments critical, especially in poorly ventilated indoor environments. The effectiveness of engineering interventions requiring minor efforts that create a negative-pressure isolation zone (IZ) for a contagious person has yet to be tested for existing residential homes.

To mitigate the risk of airborne virus transmission and maximize health protection for the population in existing …

Understanding Of Aerosol Transmission Of Covid 19 In Indoor Environment - Part 2: Approaches To Mitigation, Adama Barro, Cathal O'Toole, Jacob S. Lopez, Matthew Quinones, Sherene Moore

Publications and Research

The challenge we face in implementing solutions for new HVAC ventilation and filtration design, is to effectively improve air quality for virus mitigation without losing performance efficiency. The purpose of this improvement is to decontaminate the occupied enclosed areas, reducing the transmission of the corona virus aerosol transmission. Our research seeks reliable approaches to mitigate the further spread of aerosol transmission in indoor spaces. The methodology is to examine innovative HVAC engineering solutions that combat epidemiological problems of Covid-19 for the post-pandemic era, by researching scholarly articles and ASHRAE journals. We are achieving the goal of finding highly efficient resolutions …

Peak Reduction And Long Term Load Forecasting For Large Residential Communities Including Smart Homes With Energy Storage, Huangjie Gong, Vandana Rallabandi, Michael L. Mcintyre, Eklas Hossain, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Domestic load profiles in the residential sectors are being modified with the adoption of smart home management systems and solar generation. In addition, houses with rooftop PV behave like local generators, contributing to the growth of the penetration of PV energy. Hence, the demand for power is declining day by day. However, the increasing PV penetration causes technical challenges for the power system, such as the “duck curve”. This can be addressed through home energy management (HEM) techniques including peak shaving, load shifting with smart home devices. In this regard, electric water heaters (EWH), with high thermal mass and being …

Photocatalytic Inactivation Efficacy Of Sars-Cov-2 In Hvac Systems, Andrew J. Freeman, Sudharshan Anandan, Ernest R. Blatchley Iii, W. Travis Horton, David M. Warsinger

Discovery Undergraduate Interdisciplinary Research Internship

The coronavirus pandemic has emphasized a need for robust and reliable air purification systems in buildings; with that comes a need for a standardized testing methodology for air purification technologies in HVAC air circulation systems. One such method of air purification is photocatalytic oxidation (PCO), a mechanism in which a catalyst irradiated by light produces reactive molecules that degrade a wide range of pollutants, including the aerosols that carry COVID. This technology has primarily been used in aqueous applications, but there have recently been developments in air purification that have made it a promising contender to existing technologies. One of …

Demand Response Of Hvacs In Large Residential Communities Based On Experimental Developments, Huangjie Gong, Evan S. Jones, Rosemary E. Alden, Andrew G. Frye, Donald G. Colliver, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Heating, ventilation, and air-conditioning (HVAC) systems contribute the largest electricity usage for a residential community. Modeling of the HVAC systems facilitate the study of demand response (DR) at both the residential and the power system level. In this paper, the equivalent thermal model of a reference house was proposed. Parameters for the reference house were determined based on the systematic study of experimental data obtained from fully instrumented field demonstrators. The aggregated HVAC load was modeled based on the reference house while considering a realistic distribution of HVAC parameters derived from data that was provided by one of the largest …

The Effect Of High Efficiency Building Technologies And Pv Generation On The Energy Profiles For Typical Us Residences, Evan S. Jones, Rosemary E. Alden, Huangjie Gong, Andrew G. Frye, Donald G. Colliver, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

The penetrations of high efficiency technologies and photovoltaic (PV) generation are increasing in the residential sector. Technologies such as improved insulation and efficient HVAC systems significantly affect the energy profile of a house. This effect varies due to climate characteristics, i.e. temperature, solar radiation, relative humidity, and wind speeds. The effect of other technologies, such as efficient water heaters, lighting, or kitchen appliances, is mainly governed by human behavior, which may be represented by a schedule. This paper studies the performance of both climate-influenced and scheduled household devices among different levels of efficiency through combined computational and experimental methods. Three …

Who's Leading: The Dance Between Mini-Splits And Existing Hvac Systems, Florida Solar Energy Center, Cheryn Metzger

FSEC Energy Research Center®

Recently, many utilities across the U.S. have provided incentives for ductless mini-split heat pumps due to their relatively high efficiencies. However, when these ductless mini-splits are installed in existing homes, utilities and researchers find that they are not living up to their energy saving potential, due to a lack of coordinated controls with the existing HVAC system. The Pacific Northwest National Laboratory (PNNL), the Florida Solar Energy Center (FSEC), and The Levy Partnership are all leading projects across the country to address this problem. The goal for this body of work is to determine which control strategies provide the most …

An Aggregated And Equivalent Home Model For Power System Studies With Examples Of Building Insulation And Hvac Control Improvements, Huangjie Gong, Evan S. Jones, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

Introducing new technologies into existing residences provides opportunities for the utility to enhance a community's power system performance. To validate the benefits of such technologies, an energy model is required in which their integration with a community's power system may be simulated. It can be difficult or impossible to properly model a power system without sufficient sample data. This paper proposes a method that uses Gaussian kernel density estimation (GKDE) to calculate the aggregated net power flow of a community's distribution system with only limited sample points at each time step. Example case studies that confirm the usefulness of the …

An Iot Framework For Modeling And Controlling Thermal Comfort In Buildings, Fadi Alsaleem, Mehari K. Tesfay, Mostafa Rafaie, Kevin Sinkar, Dhaman Besarla, Parthiban Arunasalam

Durham School of Architectural Engineering and Construction: Faculty Publications

Humans spend more than 90% of their day in buildings, where their health and productivity are demonstrably linked to thermal comfort. Building thermal comfort systems account for the largest share of U.S energy consumption. Despite this high-energy cost, due to building design complexity and the variety of building occupant needs, addressing thermal comfort in buildings remains a difficult problem. To overcome this challenge, this paper presents an Internet of Things (IoT) approach to efficiently model and control comfort in buildings. In the model phase, a method to access and exploit wearable device data to build a personal thermal comfort model …

Evaluating Moisture Control Of Variable-Capacity Heat Pumps In Mechanically Ventilated, Low-Load Homes In Climate Zone 2a, Florida Solar Energy Center, Eric Martin

FSEC Energy Research Center®

The well-sealed, highly insulated building enclosures constructed by today's home building industry coupled with efficient lighting and appliances are achieving significantly reduced heating and cooling loads. These low-load homes can present a challenge when selecting appropriate space-conditioning equipment. Conventional, fixed-capacity heating and cooling equipment is often oversized for small homes, causing increased first costs and operating costs. Even if fixed-capacity equipment can be properly specified for peak loads, it remains oversized for use during much of the year. During these part-load cooling hours, oversized equipment meets the target dry-bulb temperatures very quickly, often without sufficient opportunity for moisture control. The …

Design Of An Very High Efficiency Evaporatively Cooled Mini-Split Air Conditioner, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

An in-house research project at the Florida Solar Energy Center in 2013 was conducted to evaluate the potential of an evaporatively cooled mini-split heat pump. The mini-split heat pump modified was a 1.5-ton Fujitsu model with 19.2 SEER and 10.0 HSPF energy efficiency ratings. Cooling capacity of the system is variable and ranges from 7,000 to 23,000 Btu/h.

We demonstrated that it is possible to improve the energy efficiency of the evaluated mini-split air conditioner by 21% seasonally in Florida's humid climate using an evaporative pre-cooler. Further, we showed the same apparatus was able to improve air conditioner efficiency by …

Development Of Coordination Control For Multiple Rooftop Units, Denchai Woradechjumroen, Haorong Li, Akekachai Deesiri

Durham School of Architectural Engineering and Construction: Faculty Publications

Rooftop Units (RTUs) have been widely applied in providing space heating and cooling for commercial buildings. In total, they serve over 60% of the commercial building floor space in the U.S. Even through the current control approaches of a RTU can maintain the zone temperature corresponding to a set point temperature, it performs inefficiently due to several factors such as limited sensing capability, non- coordinated local control, inherent oversizing effects and so on. In addition to unnecessary power consumptions, the current control and operation technology on RTUs also lead to the space humidity problem, equipment efficiency degradation, and premature failure. …

Investigation Of Potential Benefits Of Revising Exception 1 Under Florida Building Code, Energy Conservation, Section 101.4.7.1.1 Duct Sealing Upon Equipment Replacement, Florida Solar Energy Center, Janet Mcilvaine

FSEC Energy Research Center®

Section 101.4.7.1.1, Duct sealing upon equipment replacement (Mandatory), of the 2012 Supplement to the Florida Building Code, Energy Conservation went into effect briefly in 2013. The new section required sealing of accessible ducts at the time of HVAC equipment replacement. Exception #1 however, eliminates the requirement for ducts in conditioned space, and by doing so, effectively eliminates the sealing requirement for building cavities in conditioned space that are used as air distribution paths. However, test results show that these building cavities are often connected to adjacent unconditioned spaces, in effect they are not really in the conditioned space because they …

Initial Testing Of A Unitary Hvac System Advanced Control Module, Florida Solar Energy Center, Richard Raustad

FSEC Energy Research Center®

Testing of a unitary HVAC system advanced control module and the results.

Hvac System Analysis And Energy Audit: The Providence Athenaeum, Nicholas Farland, Trevor Larson, Justin Taylor, Cameron Wendler, Anthony Ruocco, Janet Baldwin, Arnold Robinson

Engineering and Construction Management

To evaluate the impact of potential modifications to the HVAC system the Historical Value Adding Consultants developed a building energy model. The building energy model was constructed using a Microsoft Excel spreadsheet that utilizes typical meteorological year (TMY) data to determine the average energy usage of the Athenaeum for a typical year. The model has been validated against actual energy usage and is used to identify and quantify energy savings resulting from design alternatives.

Technical Subtopic 2.1: Modeling Variable Refrigerant Flow Heat Pump And Heat Recovery Equipment In Energyplus, Florida Solar Energy Center, Richard Raustad

FSEC Energy Research Center®

The University of Central Florida/Florida Solar Energy Center, in cooperation with the Electric Power Research Institute and several variable-refrigerant-flow air conditioning (VRF AC) manufacturers, provided a detailed computer model for a VRF AC system in the United States Department of Energy's (U.S. DOE) EnergyPlus' building energy simulation tool. No other simulation tool currently has the capability to accurately model this state-of-the-art VRF heating, ventilating, and air conditioning (HVAC) equipment. Detailed laboratory testing and field demonstrations were performed to measure equipment performance and compare this performance with that predicted by the use of this new model through computer simulation.

This project …

Managing The Drivers Of Airflow And Water Vapor Transport In Existing Single-Family Homes (Revised), Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Air and water vapor are transported into and within single-family homes as a result of pathways and driving forces. Without pathways, no air or water vapor transport could occur. Likewise, without driving forces, little or no air or water vapor transport will occur. Homes always have pathways and driving forces. This report focuses on managing the driving forces that move air and water vapor across the building envelope.

A Virtual Supply Airflow Rate Meter In Rooftop Air Conditioning Units, Daihong Yu

Durham School of Architectural Engineering and Construction: Dissertations, Thesis, and Student Research

Virtual sensing technology aims to estimate difficult to measure, expensive, or new quantities by using multifarious mathematical models along with non-invasive and low-cost measurements. Such embedded intelligence is a key to improving the performance of building systems in terms of functionality, safety, energy efficiency, environmental impacts, and costs. Considering the progress that has been achieved over many various fields (e.g., process controls, automobiles, avionics, autonomous robots, telemedicine) within the last two decades, numerous intelligent features have been incorporated and enabled that would otherwise not be possible or economical.

To identify the potential opportunities and research/development needs of virtual sensing technology …