Paul Raftery

Paul Raftery
University of California, Berkeley | UCB · Center for the Built Environment

PhD Engineering

About

73
Publications
32,247
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2,313
Citations

Publications

Publications (73)
Article
In this study, we investigate methods to reduce carbon emissions from existing large commercial buildings with central natural gas-fired boilers used for space heating. This research explores opportunities to reduce natural gas use through improved building operations and through building decarbonization. We conducted one-hour interviews with 17 me...
Article
Thermal comfort in buildings is typically assessed through occupant surveys, especially for short-term thermal comfort. For long-term thermal comfort, thermal comfort standards and recent research suggest continuous physical monitoring of temperature is sufficient. However, a lack of formal rules for data representation in building automation syste...
Article
Full-text available
Ceiling-fan-integrated air-conditioning (CFIAC) is a concept in which terminal supply ducts and diffusers are replaced by vents/nozzles that jet supply air into the vicinity of ceiling fans to be mixed and distributed within the room. CFIAC distributes the supply air within the room and convectively cools the occupants. This could allow raised ther...
Article
Full-text available
Controlled air movement is an effective strategy for maintaining occupant comfort while reducing energy consumption, since comfort at moderately warmer temperatures requires less space cooling. Modern ceiling fans provide a 2–4 °C cooling effect at power consumption comparable to LED lightbulbs (2–30 W) with gentle air speeds (0.5–1 m/s). However,...
Article
The layout of ceiling fans in buildings is challenging because of the need to co-ordinate with other elements in the ceiling space, and because the resulting airflows within the occupied space interact with furniture. This study conducted detailed air speed measurements in four buildings with different room sizes, furniture configurations, ceiling...
Article
Full-text available
The Office of Sustainability at UC Berkeley leads energy and water saving campaigns on campus and has set the goal to reduce energy use intensity by an average of at least 2% annually. One of the proposed energy conservation practices is to improve ventilation efficiency. Our project primarily addresses wasted fan, cooling, and heating energy throu...
Article
Full-text available
This paper describes an open data set of 3,053 energy meters from 1,636 non-residential buildings with a range of two full years (2016 and 2017) at an hourly frequency (17,544 measurements per meter resulting in approximately 53.6 million measurements). These meters were collected from 19 sites across North America and Europe, with one or more mete...
Preprint
Full-text available
This paper describes an open data set of 3,053 energy meters from 1,636 non-residential buildings with a range of two full years (2016 and 2017) at an hourly frequency (17,544 measurements per meter resulting in approximately 53.6 million measurements). These meters are collected from 19 sites across North America and Europe, and they measure elect...
Article
The project goal was to identify and test the integration of smart ceiling fans and communicating thermostats. These highly efficient ceiling fans use as much power as an LED light bulb and have onboard temperature and occupancy sensors for automatic operationbased on space conditions. The Center for the Environment (CBE) at UC Berkeley led the res...
Article
Full-text available
Ceiling-Fan-Integrated Air Conditioning (CFIAC) is a proposed system that can greatly increase buildings’ cooling efficiency. In it, terminal supply ducts and diffusers are replaced by vents/nozzles, jetting supply air toward ceiling fans that serve to mix and distribute it within the room. Because of the fans’ air movement, the system provides com...
Article
Full-text available
The ability to inexpensively monitor indoor air speed and direction on a continuous basis would transform the control of environmental quality and energy use in buildings. Air motion transports energy, ventilation air, and pollutants around building interiors and their occupants, and measured feedback about it could be used in numerous ways to impr...
Article
This guide enables architects, designers, and engineers to maximize the many benefits of integrating ceiling fans into building systems. It introduces the advantages of using ceiling fans, describes how ceiling fans work, provides guidance and resources for designing spaces with ceiling fans and specifying ceiling fan products.
Article
Access to large amounts of real-world data has long been a barrier to the development and evaluation of analytics applications for the built environment. Open datasets exist, but they are limited in their span (how much data is available) and context (what kind of data is available and how it is described). Evaluation of such analytics is also limi...
Article
A well-recognised gap exists between measured and predicted building energy performance. Some practical assessment approaches offer the potential to reduce this gap using multiple indicators that evaluate building performance. Such approaches rely on subjective analysis of indicators’ relative weights but are typically limited to a fixed assessment...
Article
For radiant cooling to maintain equivalent comfort conditions as all-air cooling it must remove more heat from a space, the peak space heat extraction rate must be larger, and the peak must occur earlier. In this article, we assess how the magnitudes of these differences are influenced by heat gain characteristics and by the use of natural ventilat...
Article
Radiant cooling and heating systems provide an opportunity to achieve significant energy savings, peak demand reduction, load shifting, and thermal comfort improvements compared to conventional all-air systems. As a result, application of these systems has increased in recent years, particularly in zero-net-energy (ZNE) and other advanced low-energ...
Article
We measured indoor air speeds generated by ceiling fans in 78 full-scale laboratory tests. The factors were the room size, fan diameter, type, speed, direction (up or down), blade height, and mount distance (i.e. blade to ceiling height). We demonstrated the influence of these factors, showing that the most significant are speed, diameter and direc...
Article
The current standard procedure for design sizing of cooling systems is not well suited for design of buildings with radiant cooling. There are several reasons that the standard design procedure for radiant cooling systems (ASHRAE Systems & Equipment 2016 Chapter 6: Radiant Heating and Cooling) is flawed, including that the current standard definiti...
Conference Paper
Full-text available
Access to large amounts of real-world data has long been a barrier to the development and evaluation of analytics applications for the built environment. Open data sets exist, but they are limited in their span (how much data is available) and context (what kind of data is available and how it is described). Evaluation of such analytics is also lim...
Article
Full-text available
Ceiling fans are a traditional approach for increasing occupant comfort and are well-established in residential application in many parts of the world. However, they are infrequently included in commercial spaces even though they have the potential to bring benefits including increased occupant comfort and decreased energy use either through raised...
Article
Full-text available
We developed a new method to estimate useful versus wasted hot water reheat energy using data obtained from typically installed instrumentation that applies to all pressure independent VAV terminal units with discharge air temperature sensors. We evaluated the method using a year of 1 min interval data for a 11,000 m² building with 98 terminal rehe...
Conference Paper
Full-text available
Cooling demands are a major driver of energy consumption in buildings, and is mostly performed using systems based on the refrigeration cycle, an energy and cost intensive process. To investigate the potential of eliminating the refrigeration cycle from a building design in Californian climates, we created a single zone EnergyPlus model that uses a...
Article
We present a novel pulsed flow control method (PFM) using a two-position valve to regulate the capacity of radiant slab systems. Under PFM, the on-time duration of the valve is short (compared to all prior work, e.g. 4-minute), and fixed, while the off-time varies. We present a novel, open-source, finite difference model that assesses three-dimensi...
Article
A personal comfort model is a new approach to thermal comfort modeling that predicts individuals’ thermal comfort responses, instead of the average response of a large population. However, securing consistent occupant feedback for model development is challenging as the current methods of data collection rely on individuals’ survey participation. W...
Article
Full-text available
This paper describes a new supply air temperature control strategy for multi-zone variable air volume systems. We developed the strategy with the intent that it is simple enough to implement within existing building management systems. At 5-minute intervals, the strategy estimates the cost of fan, heating and cooling energy at three different suppl...
Article
Thermally activated building systems have the potential to achieve significant energy savings, yet, the exposed concrete may also create acoustical challenges due to the high reflectivity of the hard surface. Free-hanging acoustical clouds reduce the acoustical issues, but also the cooling capacity of a radiant chilled ceiling system. Fan-induced a...
Article
There is little knowledge from occupied buildings of the impact of radiant heating and cooling systems on indoor environmental quality aspects such as thermal comfort, indoor air quality, and acoustics. We present indoor environmental quality survey results from 3892 respondents in 60 office buildings located in North America; 34 of which used all-...
Article
Full-text available
Detailed insights on energy use are missing for the building stock in Singapore which may aid with energy consumption reductions through a targeted approach. Therefore, we created two whole building energy models for a large commercial office building in the tropics; representing a fully glazed and a concrete façade. We used Singapore's current bui...
Article
This paper presents a new controller for high thermal mass radiant systems that can be implemented within a typical Building Automation System. We illustrate its performance using an EnergyPlus model representing a single zone, middle floor of an office building in Sacramento, California. The results of a small sensitivity analysis show that when c...
Technical Report
Full-text available
Radiant cooling and heating systems provide an opportunity to achieve significant energy savings, peak demand reduction, load shifting, and thermal comfort improvements compared to conventional all-air systems, and as a result, application of these systems has increased in recent years. However, due to the relatively new and unfamiliar nature of ra...
Technical Report
Full-text available
Radiant cooling and heating systems provide an opportunity to achieve significant energy savings, peak demand reduction, load shifting, and thermal comfort improvements compared to conventional all-air systems, and as a result, application of these systems has increased in recent years. However, due to the relatively new and unfamiliar nature of ra...
Article
Radiant slab systems have the potential to achieve significant energy savings, yet, when applied in the ceiling (e.g., thermally activated building system) the exposed concrete may also create acoustical challenges due to the high reflectivity of the hard surface. Balancing all of the building indoor environmental quality factors is important in th...
Article
Full-text available
Typical Variable Air Volume (VAV) terminals spend the majority of time at their minimum airflow setpoints. These are often higher than the minimum ventilation requirements defined by code, resulting in excess energy use and a risk of over-cooling the spaces. We developed and tested a Time-Averaged Ventilation (TAV) control strategy in an institutio...
Article
Underfloor air distribution (UFAD) systems use the underfloor plenum beneath a raised floor to provide conditioned air through floor-mounted diffusers, which typically discharge cool air with both horizontal and vertical momentum components. These systems usually create a vertical temperature stratification when in cooling mode and this has an impa...
Article
Full-text available
In this paper we present the results from field studies of two low-energy office buildings in California, both using radiant slab ceiling systems (thermally activated building systems, TABS) for primary cooling and heating in the buildings. Both buildings are certified LEED Platinum and incorporate a wide range of energy efficient technologies and...
Conference Paper
Full-text available
Personal Comfort Systems (PCS) are capable of maintaining occupant comfort in buildings despite large deviations from recommended "comfortable" temperatures. We present a novel digital controller for a well-studied (previously analog) PCS, allowing it to report real-time telemetry and respond to programmatic actuation requests. This enables the est...
Article
We assess the impact that furniture and contents (i.e. internal mass) have on zone peak cooling loads using a perimeter zone model in EnergyPlus across 5400 parametric simulation runs. The zone parameters were HVAC system type (overhead, underfloor, and thermally activated building system (TABS)), orientation, window to wall ratio, and building env...
Article
Full-text available
The contribution of buildings towards total worldwide energy consumption in developed countries is between 20 and 40 %. This is expected to rise by an average rate of 1.5 % per annum over the next 20 years. Heating ventilation and air conditioning (HVAC) and more specifically air handling units (AHUs) energy consumption accounts on average for 40 %...
Article
Full-text available
Heating Ventilation and Air Conditioning (HVAC) system energy consumption on average accounts for 40% of an industrial sites total energy consumption. Studies have indicated that 20 – 30% energy savings are achievable by recommissioning Air Handling Units (AHUs) in HVAC systems to rectify faulty operation. Studies have also demonstrated that on-goi...
Article
Full-text available
Studies have indicated that 20–30 % HVAC system energy savings are achievable by recommissioning air handling units (AHU) to rectify faulty operation. Studies have also demonstrated that on-going commissioning of building systems for optimum efficiency can yield savings of an average of over 20 % of total energy cost. Automated fault detection and...
Conference Paper
Full-text available
This paper outlines a methodology for the calibration of detailed building energy simulation (BES) models using an analytical optimisation approach. The approach combines evidence-based model development with statistical Monte-Carlo based optimisation techniques. The first stages of the proposed calibration methodology are applied to a 700m2 natura...
Conference Paper
Full-text available
Heating Ventilation and Air Conditioning (HVAC) system energy consumption on average accounts for 40percent of an industrial sites total energy consumption. Studies have indicated that 20 - 30 percent energy savings are achievable by re-commissioning HVAC systems to rectify faulty operation with savings of over 20 percent of total energy cost possi...
Conference Paper
Full-text available
This paper describes the calibration of a detailed whole-building energy simulation model of a naturally ventilated building to hourly measured data. This demonstrates the application of an evidence-based analytical optimisation approach described in a previous paper (Coakley et al. 2011). The methodology is applied to the following case study, nat...
Article
This paper presents the key factors methodology that supports energy managers in determining the optimal building operation strategy in relation to both energy consumption and thermal comfort. The methodology is supported by the utilization of calibrated building energy simulation models that match measured data gathered by an extensive measurement...
Article
In this paper, an EnergyPlus model was used to simulate the operation of a novel integrated HVAC system. This system combines an underfloor air distribution system with a cooled radiant ceiling slab. A cooling tower supplies water to pre-cool the structural slabs during the night and early morning period. The paper compares the performance of this...
Conference Paper
Full-text available
Globally buildings consume more than 40% of primary energy and are responsible for in excess of 30% CO2 emissions. Building Energy Simulation (BES) models can play a significant role in the design and optimisation of buildings. Simulation models may be used to assess the cost-effectiveness of Energy-Conservation Measures (ECMs) in the design stage...
Article
This paper demonstrates a systematic, evidence-based methodology for calibrating whole building energy models. The methodology uses version control software to store a complete history of the calibration process, including the evidence on which decisions were made. This paper details the calibration of a whole building energy model to hourly energy...