Building operations are a significant consumer of energy and contributor to carbon emissions in the U.S. and around the globe. Energy audits offer significant potential in reducing building energy use by providing tailored recommendations involving equipment upgrades, operational adjustments and building recommissioning. However, energy audits are a time intensive process that requires significant experience and training. This causes high costs related to performing an audit and prevents many businesses from having an audit completed. Automating the audit process will not only reduce the cost of audits, but clients will be provided with more repeatable and accurate recommendations based on improved data collection and analysis. Previous work and the current state of the art of robotic auditing tools are discussed in this paper, followed by open challenges and future possibilities of autonomous vehicles for conducting audits.

A building owner can use a realistic energy model to understand the future building’s energy performance. But what happens when the design energy model predicted energy use and the utility bills have a significant variance? Can adjusting the energy model to match the utility bill, or calibrating it, successfully identify the cause of the variance? Will this show strategies to bring the actual energy use back in line with the predicted energy use? This paper reviews the calibration effort of a Medical Office Building where the actual energy use was significantly above the predicted energy use.

How energy efficient can commercial and multifamily buildings become in the near future if first cost is not considered? The paper describes how building energy simulation modeling was used to try to answer this question. The first step was to assemble a list of energy efficiency measures that can be included in the design of non-residential buildings. The list included both commonly used and cutting edge energy efficiency measures with the goal of being comprehensive, at least for measures that can be modeled. Input was sought from many people to ensure that the list of measures did not exclude any important ones.

Automated tools facilitate an ongoing commissioning process to improve occupant comfort, ensure the persistence of correct system operation and reduce energy consumption. These tools decrease the time and the skill level required to carry out necessary quality assurance measures, and as a result they enable more thorough testing of building heating, ventilating and air-conditioning (HVAC) systems. This paper describes the algorithm developed by the U.S. National Institute of Standards and Technology (NIST) to analyze chiller loops and presents the results of a passive monitoring investigation using field data obtained from BACnet controllers and field validation of the findings. The tool was successful in detecting faults in system operation in its first field implementation for performance monitoring.

Design of chilled water plants has a very large impact on building energy uses and energy operating costs. This paper proposes a design tool for optimal design of chilled water plants. The tool that integrates system models with a genetic algorithm optimization solver minimizes the life cycle cost by finding the design variables such as chilled water and condenser piping diameters, chilled and condenser water temperature differences and chilled water supply temperature. The proposed modeling methods depend on detailed cooling load analysis and head and energy calculations. The pump head calculations including piping, all fittings, valves, and devices are achieved by using the Darcy-Weisbach equation with given flow parameters. The energy calculations are done by using generic chiller, fan, and pump models. The hourly cooling loads need to be obtained from any energy simulation software. The method is tested on an existing three-story, eighty-eight thousand square foot building.

A preliminary evaluation of the performance of a consumer-based control system was conducted by the Oak Ridge National Laboratory (ORNL) and Southwest Gas as part of a cooperative research and development agreement (CRADA) authorized by the Department of Energy (DOE) (Mahderekal et al. (2013). The goal of the research was to evaluate the low-cost approach as a solution for implementing a supervisory control system for a residential gas-operated heat pump. This technical paper explains the research process. A robust data set was produced that allowed detailed assessment of the reliability and the operational performance of the newly developed control system. Experiences gained from the test provided important points of improvement for subsequent evolution of the heat pump technology.

Under ASHRAE Research Project 1699 (RP-1699) we provide an update of the data used both in the “Climatic Design Information” chapter of the 2017 ASHRAE Handbook of Fundamentals and in ANSI/ASHRAE Standard 169, “Weather Data for Building Design Standards”. A total of 8118 stations were successfully processed worldwide representing a 26% increase compared to 2013. Reported elements now include monthly average wind speed, wet bulb temperature return periods and monthly-average daily all-sky global horizontal solar radiation. A number of pre-screening and post-processing tools were developed in order to ensure a reliable and useful product.

Air-leakage through building envelopes causes significant energy losses. Air-tightness codes do not account for air-leakage due to wind-driven pressure gradients and thermal resistance codes do not consider any air-leakage effects. Air-leakage needs to be included codes to understand the effects on thermal performance. We calculated effective thermal resistances in 103 locations considering air-leakage effects, to see effects on thermal performance. Simulations showed decreased thermal resistances and increased energy losses in every climate. Varying levels of thermal performance demonstrate relative importance of air-tightness in different climates. Results imply current codes do not accurately represent thermal performance and where air-tightness matters most.

This paper describes two of the unique elements of the advanced control sequences developed for ASHRAE Research Project 1455 (RP-1455): automatic fault detection and diagnostics (AFDD) and hierarchical alarm suppression. AFDD is a method used to identify fault conditions and provide possible diagnoses. Hierarchical fault suppression is a method based on hierarchical structure used to reduce the incidence of nuisance alarms. It is written by the members of the research team and is part of the deliverables for this research project. AFDD and hierarchical alarm suppression will further enhance the ability of DDC systems to make intelligent alarm distribution and management decisions.

An analytical study is carried out to assess the impact of corrections to nominal test conditions on the measured energy factor for residential water heaters. While test conditions are specified in the method of test, the difficulty in exactly achieving these test conditions in the laboratory necessitates a computational approach to correct the results to nominal conditions. This paper examines the magnitude of those corrections for a range of water heaters of various fuel type, heating method, and size across a number of potential draw volumes during a 24 hour simulated use test.

The impact of the high power requirements of large residential tankless electric resistance water heaters on electric system distribution wiring, transformers, breakers, and other equipment is an area of concern for both electric utilities and builders. This study analyzes how probable and worst case diversified electrical demand of large (28 kW) residential tankless electric water heaters compares to that of 4.5 kW storage water heaters in residential applications as a function of number of households on a given electrical distribution circuit.

Information on hotel hot water use patterns has been limited until now, resulting in most hotel hot water systems being designed using extremely old hot water use data (45-80 years old) that predate the introduction of water and energy efficient fixtures and appliances. In recognition of this fact, ASHRAE funded research project 1544 “Establishing Benchmark Levels and Patterns of Commercial Hot Water Use – Hotels” to both develop a monitoring methodology that could be duplicated by others to collect hot water use data from a larger number of hotels and to obtain updated hot water use information from at least two hotels. This paper compares hot water use results collected for a “travel” hotel which had neither meeting rooms nor food service and a “business” hotel which had both.

This is the fifth paper in a series of technical papers written to describe results of ASHRAE research project 1544. This paper builds on information presented in the project final report, the three previously published papers to present information on using the updated data to select water heating systems for hotels of any desired size and compares results of this sizing method to other hotel hot water system sizing methods described in the ASHRAE Service Water Heating Handbook Chapter through the use of examples.

Knowledge of occupants' interactions with building components and systems and how indoor environments are influenced in response to occupant behaviors is highly beneficial to operate and maintain existing building more efficiently and to design new buildings to be more comfortable and energy-conscious. This paper provides insight in this regard. To this end, occupant behaviors and energy flows are being monitored in an academic building in Ottawa, Canada. The paper presents results of this monitoring campaign on occupants' presence and behaviors, indoor environmental conditions, and energy demands in various offices.

When modeling an HVAC system using fan powered terminal units with EnergyPlus, the user must enter values for fan total pressure rise and fan/motor efficiency. A recent study found that for an 8 inch inlet (203 mm) series fan powered terminal unit, the fan total pressure was considerably lower than values commonly recommended in online training sources. Values in that study were on the order of 0.25 in. w.g. (63 Pa) and not 1.5 or even as much as 3 in. w.g. (374 – 747 Pa). Manufacturer’s performance data were used to verify and extend VAV fan powered terminal unit total pressure rise measurements as determined in a previous study.

The current version of ASHRAE Standard 170 procludes natural ventilation in all spaces in healthcare facilities. This work-group suggests it should be allowed in most healthcare spaces, except for Operating Rooms, Procedure Suites, Sterile Core areas, Interventional Radiology or Cardiology Spaces, Airborne Isolation Areas, and Protective Environments. Natural or mixed-mode ventilation designs may offer some benefits. Among the most likely are energy reduction and enhanced occupant satisfaction. Less likely benefits may include enhanced indoor air quality and a more beneficial microbiome. When considering natural ventilation in health care, designers must fully address the fundamental challenges of space appropriateness, climate appropriateness, acoustics, security, and outdoor air quality. Projects implementing natural ventilation should anticipate commissioning challenges.

The energy consumption of the heating and cooling coils of the air handling units of an educational building with multiple laboratories has been evaluated and suitable energy recovery methods were assessed in an attempt to reuse the energy lost in the exhaust air stream and promote energy conservation while complying with the current building codes. The HVAC system of Life Sciences II (LS II) building of Southern Illinois University Carbondale, is a constant air volume (CAV), 100% outside air (OA) system due to the many laboratories in the building. It is one of the most energy intensive buildings on campus.

The adoption of energy efficient standards significantly cut the energy consumption in buildings by reducing envelope heat transfer and internal heat gain. These energy efficiency measures reduce not only the electrical load but also the cooling load as well as the supply airflow rate. As a result, additional reheat is typically required to maintain the minimum airflow setpoint under partial space cooling loads for conventional air handling units (AHUs) and may degrade the effectiveness of energy efficient measures. The AHUs with return air bypass (RAB) provides an alternative to reduce additional reheating and overcooling at the minimum airflow rate with good space humidity control. The purpose of this paper is to investigate the energy and control performance of the AHUs with RAB under different operating conditions through simulations.