Managing a sustainable built environment with a large number of buildings rests on the ability to assess and improve the performance of the building stock over time. Building stock models are cornerstones to the assessment of the combined impact of energy-related building interventions across different spatial and temporal scales. However, such models, particularly those accounting for both physical formulation and social behaviors of the underlying buildings, are still in their infancy. This research strives to more thoroughly examine how buildings perform aggregately in energy usage by focusing on how to tackled three major technical challenges: (1) quantifying building energy performance in an objective and scalable manner, (2) mapping building stock model space to real-world data space, and (3) quantifying and evaluating energy intervention behaviors of a building stock. This thesis hypothesizes that a new paradigm of aggregation of large-scale building stocks can lead to (1) an accurate and efficient intervention analysis model and (2) a functionally comprehensive decision support tool for building stock energy intervention analysis. Specifically, this thesis presents three methodologies. To address the first challenge, this thesis develops a normative building physical energy model that can rapidly estimate single building energy performance with respect to its design and operational characteristics. To address the second challenge, the thesis proposes a statistical procedure using regression and Markov chain Monte Carlo (MCMC) sampling techniques that inverse-estimate building parameters based on building stock energy consumption survey data. The outcomes of this statistical procedure validate the approach of using prototypical buildings for two types of intervention analysis: energy retrofit and demand response. These two cases are implemented in an agent-based modeling and simulation (ABMS) framework to tackle the third challenge. This thesis research contributes to the body of knowledge pertaining to building energy modeling beyond the single building scale. The proposed framework can be used by energy policy makers and utilities for the evaluation of energy retrofit incentives and demand-response program economics.

In the United States, commercial and residential buildings are responsible for 40% of total energy consumption, which provides an important opportunity for energy impact. As we spend the majority of our active moments during the day in transportation, commercial buildings, streets, and infrastructure, some of the greatest opportunities to reduce energy usage occur when we are outside of the home. A large percentage of energy consumption in the built environment directly or indirectly services humans; thus, there is a significant amount of untapped energy savings that can be achieved by involving humans in the optimization process. By including occupants in the building co-optimization process, we can gain a better understanding of individual energy responsibility and significantly improve energy consumption, thermal comfort and air quality over non human-in-the-loop systems and strategies. First, we present ePrints, a scalable energy footprinting system capable of providing personalized energy footprints in real-time. ePrints supports different apportionment policies, with microsecond-level footprint computation time and graceful scaling with the size of the building, frequency of energy updates, and rate of occupant location changes. Finally, we present applications enabled by our system, such as mobile and wearable applications to provide users timely feedback on the energy impacts of their actions, as well as applications to provide energy saving suggestions and inform building-level policies. Next, we extend the idea of energy footprinting to the city-scale with CityEnergy a city-scale energy footprinting system that utilizes the city's digital twin to provide real-time energy footprints with a focus on 100% coverage. CityEnergy takes advantage of existing sensing infrastructure and data sources in urban cities to provide energy and population estimates at the building level, even in built environments that do not have existing or accessible energy or population data. CityEnergy takes advantage of LFTSys, a low frame-rate vehicle tracking and traffic flow system that we implement on New York City's traffic camera network, to aid in building population estimates. Evaluations comparing CityEnergy with building level energy footprints and city-wide data demonstrate the potential for CityEnergy to provide personal energy footprint estimates at the city-scale. We then tackle the challenge of involving humans in the building energy optimization process by developing recEnergy, a recommender system for reducing energy consumption in commercial buildings with human-in-the-loop. recEnergy learns actions with high energy saving potential through deep reinforcement learning, actively distribute recommendations to occupants in a commercial building, and utilize feedback from the occupants to better learn four different types of energy saving recommendations. Over a four week user study, recEnergy improves building energy reduction from a baseline saving (passive-only strategy) of 19% to 26%. Finally, we extend the recommender system to co-optimize over energy consumption, occupant thermal comfort, and air quality. The recommender system utilizes a multi-task deep reinforcement learning architecture, and is trained using a simulation environment. The simulation environment is built using different models trained on data captured from a digital twin of a real deployment. To measure occupant thermal comfort, the digital twin utilizes a real-time comfort estimation system that extracts and integrates facial temperature features with environmental sensing to provide personalized comfort estimates. We studied three different use cases in this deployment by varying the objective weights in the recommender system, and found that the system has the potential to further reduce energy consumption by 8% in energy focused optimization, improve all objectives by 5-10% in joint optimization, and improve thermal comfort by up to 21% in comfort and air quality focused optimization by incorporating move recommendations.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The thesis was initiated by a Consulting Engineering Company (KV3) as a research project to investigate various options in which the efficiency and energy utilisation of conventional air conditioning systems may be enhanced by using alternative and renewable energy. Initially, eight options had been identified and through a process of determining the degree of commercialisation the alternative options were reduced to three. These options, referred to as the sustainable cooling alternatives, are active mass cooling, night flushing and roof cooling system. The roof cooling system comprised a roof-pond, roof-spray, pump and storage tank. The roof cooling system was mathematically and experimentally modelled. The roof cooling experiment was performed under a variety of weather conditions with the roof-pond and storage tank temperatures continuously recorded. The experimentally recorded temperatures were compared to the temperatures generated by the theoretical simulation calculations for the same input and weather conditions. Good agreement was found between the mathematical and experimental model. The largest discrepancy found between the simulated temperature and the experimental temperature was in the order of 1 ºC. A one-room building has been assumed to serve as a basis to which the sustainable cooling alternatives could be applied to for theoretical simulation. The one-room building had four façade walls and a flat roof slab. Night flushing, active mass cooling and the roof cooling system were applied to the one-room building such that the room air temperature and space cooling load could theoretically be simulated. The theoretical simulations were also repeated for the case where the roof-pond and roof-spray were applied as standalone systems to the one-room building. The theoretical simulation calculations were performed for typical summer weather conditions of Stellenbosch, South Africa. Under base case conditions and for a room thermostat setting of 22 ºC the peak cooling load of the one-room building was 74.73 W/m². With the application of night flushing between the hours of 24:00 and 07:00, the room cooling load was reduced by 5.2% by providing 3.9 W/m² of cooling and reducing the peak room temperature by 1.4 ºC. The active mass cooling system was modelled by supplying water at a constant supply temperature of 15 ºC to a pipe network embedded in the roof slab of the one-room building. The sea may typically be considered as a cold water source for buildings situated at the coast. The active mass cooling system reduced the peak cooling load of the one-room building by 50% by providing 37.2 W/m² of cooling and reducing the peak room temperature by 6.7 ºC. When the roof-spray and roof-pond systems were applied as standalone systems to the oneroom building, the peak cooling load of the one-room building could be reduced by 30% and 51% respectively. This is equivalent to 22.3 W/m² of peak cooling by the roof-spray and 38 W/m² of peak cooling by the roof-pond. The roof-spray reduced the peak room temperature by 3.71 ºC while the roof-pond reduced the peak room temperature by 5.9 ºC. Applying the roof cooling system to the one-room building produced 46 W/m² of peak cooling which resulted in a 61.1% reduction in peak cooling load. The roof cooling system reduced the peak temperature by 8 ºC. By comparing the sustainable cooling alternatives, the roof cooling system showed to be the most effective in reducing the one-room building peak cooling load. Over a 24 hour period the roof cooling system reduced the net heat entry to the one-room building by 57.3%. In a further attempt to reduce the peak cooling load, the sustainable cooling alternatives were applied in combinations to the one-room building. The combination of night flushing and roof-spray reduced the peak cooling load by 36% while a combination of night flushing and active mass cooling reduced the peak cooling load by 55%. Combining night flushing with the roof-pond also yielded a 55% peak cooling load reduction. The combination of roofpond, active mass cooling and night flushing provided 51 W/m² of cooling which corresponded to a 68% reduction in peak cooling load. Utilising the sustainable cooling alternatives in a combination in the one-room building gave improved results when compared to the case where the sustainable cooling alternatives were employed as standalone systems. It is illustrated by means of a sensitivity analysis that the ability of the roof cooling system to produce cool water is largely influenced by ambient conditions, droplet diameter and roofspray rate. Under clear sky conditions, an ambient temperature of 15 ºC, relative humidity of 80%, a roof-spray rate of 0.02 kg/sm² and a roof-pond water level of 100mm, water could be cooled at a rate of 113 W/m². The roof-spray energy contributed to 28 W/m² whilst the night sky radiation was responsible for 85 W/m² of the water cooling. It must however be noted that the water of the roof cooling system can never be reduced to a temperature that is lower than the ambient dew point temperature. / AFRIKAANSE OPSOMMING: Die tesis is geïnisieer deur ‘n Raadgewende Ingenieurs Maatskappy (KV3) as a navorsingsprojek om verskeie opsies te ondersoek waarmee die effektiwiteit en energie verbruik van konvensionele lugversorgingstelsels verbeter kan word deur middel van alternatiewe en hernubare energie. Agt opsies is oorspronglik geïdentifiseer en deur middel van ‘n proses waarby die graad van kommersialisering van hierdie alternatiewe maniere bepaal is, kon die opsies verminder word tot drie. Hierdie opsies, ook verwys na as die volhoubare verkoelingsalternatiewe, sluit in aktiewe massa verkoeling, dakverkoeling en nagventilasie. Die dakverkoelingstelsel bestaan uit dakwater, ‘n dakspuit, ‘n pomp en ‘n stoortenk. Die dakverkoelingstelsel is wiskundig en eksperimenteel gemodelleer. Die dakverkoelingseksperiment is uitgevoer onder ‘n verskeidenheid van weersomstandighede. Die dakwater asook die stoortenk se water temperatuur is voortdurend aangeteken. Dieselfde weer- en insetkondisies is gebruik vir die simulasie berekening en die temperature van die stoortenk se water en die dakwater is vergelyk met die temperatuurlesings van die eksperimentele werk. Die temperature van die eksperimentele lesings het goed vergelyk met die temperatuur simulasie berekeninge. Die grootste verskil tussen die simulasie en eksperimentele temperatuur was in die orde grootte van 1 ºC. ‘n Een-kamer gebou is aangeneem om as basis te dien waarop die volhoubare verkoelingsalternatiewe aangewend kon word vir teoretiese simulasie. Die een-kamer gebou het uit vier buite mure en ‘n horisontale beton dak bestaan. Nag ventilasie, aktiewe massa verkoeling en die dakverkoelingstelsel is toegepas op die een-kamer gebou en die kamer se verkoelingslas asook die kamer se lugtempertuur is teoreties gesimuleer. Die teoretiese simulasies is ook herhaal vir die geval waar die dakwater and dakspuitstelsel apart aangewend is op die een-kamer gebou. Die teoretiese simulasie berekeninge is uitgevoer vir tipiese somer weersomstandighede vir Stellenbosch, Suid Afrika. Onder basisgeval omstandighede, waar die een-kamer gebou gesimuleer is, sonder enige volhoubare verkoelingsalternatiewe en ‘n termostaat verstelling van 22 ºC, is die piek verkoelingslas bereken as 74.73 W/m². Met die toepassing van nagventilasie tussen die ure 24:00 en 07:00 was die piekverkoelingslas van die kamer verminder met 5.2% deur 3.9 W/m² se verkoeling te verskaf en die piekkamer temperatuur te verminder met 1.4 ºC. Aktiewe massa verkoeling is gesimuleer deur water teen ‘n konstante temperatuur van 15 ºC te verskaf aan ‘n pypnetwerk, geïnstalleer in the beton dak, van die een-kamer gebou. Geboue geleë aan die kus kan tipies seewater oorweeg as ‘n bron van koue water. Aktiewe massa verkoeling het die piekverkoelingslas van die een-kamer gebou verminder met 50% deur 37.2 W/m² se verkoeling te verskaf en die piekkamer temperatuur te verminder met 6.7 ºC. Wanneer die dakspuit- en dakwaterstelsel aangewend is op die een-kamer gebou as enkel staande stelsels, is die piekverkoelingslas verminder met 30% en 51% onderskeidelik. Dit is ekwivalent aan 22.3 W/m² se verkoeling vir die dakspuitstelsel en 38 W/m² se verkoeling vir die dakwaterstelsel. Die dakspuitstelsel het die piekkamer temperatuur verminder met 3.71 ºC terwyl die dakwaterstelsel ‘n 5.9 ºC verlaging in piekkamer temperatuur tot gevolg gehad het. Die dakverkoelingstelsel het 46 W/m² se piekverkoeling verskaf wat ‘n 61.1% vermindering in piekverkoelingslas tot gevolg gehad het. Die ooreenstemmende piek temperatuur vermindering is 8 ºC. Deur die verskeie volhoubare verkoelingsalternatiewe met mekaar te vergelyk, word getoon dat die dakverkoelingstelsel die mees effektiefste manier is om die een- kamer se piekverkoelingslas te verminder. Oor ‘n tydperk van 24 uur het die dakverkoelingstelsel die totale energievloei na die een-kamer gebou met 57.3% verminder. In ‘n verdere poging om die piekverkoelingslas te verminder, is die volhoubare verkoelingsalternatiewe toegepas in kombinasies op die een-kamer gebou. Die kombinasie van nagventilasie met die dakspuitstelsel het die piekverkoelingslas met 36% verminder, terwyl ‘n kombinasie van nagventilasie en aktiewe massa verkoeling ‘n 55% vermindering in piekverkoelingslas tot gevolg gehad het. Die kombinasie van dakwater en nagventilasie het ook ‘n piekverkoelingslas vermindering van 55% teweeggebring. Die kombinasie van dakwater, aktiewe massa verkoeling en nagventilasie het 51 W/m² se verkoeling veskaf, wat ooreenstem met ‘n 68% vermindering in piekverkoelingslas. Deur die volhoubare verkoelingsalternatiewe in kombinasies toe te pas op die een-kamer gebou, kon beter resultate verkry word toe dit vergelyk is met die geval waar die volhoubare verkoelingsalternatiewe as enkelstaande stelsels toegepas is. Dit is geïllustreer deur middel van ‘n sensitiwiteitsanalise dat die vermoë van die dakverkoelingstelsel om koue water te produseer, beïnvloed word deur buitelug kondisies, waterdruppel deursnee en dakspuit massa vloeitempo. Onder die oop hemelruimteomstandighede, ‘n buitelug temperatuur van 15 ºC, ‘n relatiewe humiditeit van 80%, ‘n dakspuit massa vloeitempo van 0.02 kg/sm² en dakwatervlak van 100 mm, kon water verkoel word teen ‘n tempo van 113 W/m². Die dakspuit gedeelte het 28 W/m² bygedra terwyl die nagruim radiasie sowat 85 W/m² se verkoeling verskaf het. Daar moet egter kennis geneem word dat die water temperatuur van die dakverkoelingstelsel nooit verminder kan word tot onder die buitelug doupunttemperatuur nie.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Energy efficiency in the operation of buildings is becoming increasingly important with a growing emphasis on sustainability and reducing environmental impacts of irresponsible energy usage. Improvements have been made both on the technology side of energy efficiency and on the human behavior side. However, when changing human behavior, it is critical to find energy conservation measures that will maintain comfort for occupants. This paper analyzes how this can be done by implementing a modulating temperature schedule based on the concept of alliesthesia, which states that pleasure is observed in transient states. EnergyPlus simulations were used to show that in cooling applications, this type of scheduling can produce significant energy savings. However, energy savings are not predicted for the same type of scheduling for heating applications. Thermal comfort was examined with a cooling experiment and a separate heating experiment, each lasting 45 minutes and taking place during the corresponding season. The experiments showed that modulating temperatures can cause occupants to experience more pleasure than if the temperature remained constant in a cooled space, whereas modulating temperatures had a negative impact on comfort relative to the constant temperature in the heated space. This presents evidence for an ideal opportunity for cooling applications by implementing modulating temperature schedules: an increase in thermal pleasure accompanied by a decrease in cooling energy.

A Post-Occupancy Energy Analysis of the Gwinnett Environmental and Heritage Center conducted with the view of recommending optimizations that result in energy savings.

The National Park Service has provided guidance to the public for years regarding weatherization measures for historic houses. Some of this guidance advised against installing wall insulation, citing the potential for moisture condensation resulting in structural damage. With the passage of the American Recovery and Reinvestment Act in 2009, a substantial investment was made in the 30 year old Weatherization Assistance Program, which provides federal funds for home weatherization. The program has used wall insulation with no reported problems and proven energy savings. Some State Historic Preservation Offices (who review federally funded actions) protested the use of wall insulation based on the NPS guidance, especially Preservation Brief #3. This thesis describes the fundamental differences between the preservation community’s approach to energy efficiency as compared to the weatherization community’s approach, and addresses some concerns of historic preservation officials regarding perceived potential damage of some weatherization measures, including wall insulation. / Introduction : HP and DOE programmatic agreement -- Energy efficiency guidance from the historic preservation community -- Guidance from the weatherization community -- Analysis of differences between preservation guidance and DOE guidance -- Recommendations. / Department of Architecture

No description available.

No description available.

M.Sc. / This study compares the electricity consumption of two buildings, of similar architectural design, in Simba Office Park, Sandton, in Johannesburg. One of the buildings (Block AB) has not been retrofitted for energy efficiency, whilst the other building (Block C) is a retrofitted building. The hypothesis postulates that the retrofitted building would use less energy than the non-retrofitted one. The research methodology employed has been used internationally, as in the case reported by Levine et al. (1996), who did a study in the United States of America on retrofitting for achieving energy efficiency. Dong et al. (2005) investigated the energy savings due to the retrofitting of old Singaporean commercial office buildings. In this case, six buildings were compared before and after retrofitting, using utility bill and weather data. There have also been similar studies in China (Xu et al, 2006) and Budapest (Urge-Vorsatz & Novikova, 2008). The Budapest study also unpacked the cost of retrofitting. Using methods advocated by Probst (2004), Yalcintas (2008) and Yalcintas & Kaya (2009) for collecting data on floor space, building parameters and design, this study also collected electricity consumption data based on meter readings for the same blocks over the period March 2009 to April 2010. The retrofitting measures were documented and the associated costs noted. Interviews were conducted with key personnel such as the Central Energy Fund (CEF) House executives, the site electrical engineer, the developer, and Simba Office Park managers. Block AB had the least number of energy-efficient installations. Block C was found to be fully retrofitted, at a cost of more than R4 million. However, the energy management system, required to manage and monitor energy use, was only fully installed by November 2009. The results of this study are significant. It was found that energy consumption for Block C far exceeded that for Block AB. Thus, in this case, retrofitting did not reduce electricity consumption. The results demonstrate that in order to fully understand energy use, data collection and analysis must be ongoing. This verifies the findings of Ali (2008), Armstrong (2009) and Yalcintas & Kaya (2009) who found that we need to shift from managing buildings to managing energy use and assess and verify any recorded savings to ensure energy conservation. Computer-based building management systems play a major role in such management. Such a system was only partially in use in Block C for the duration of the study period. Thus, another finding was that the energy management system needs to be fully operational in real time, or else energy efficiencies cannot be achieved and data sets will be incomplete. This conclusion reflects the findings of Hirst (1980).