The healthcare sector represents a great opportunity and a great challenge for high-tech energy efficiency.
Hospitals are among the most energy intensive of all buildings owing to 24/7 operation, intensive ventilation and air filtration requirements, complex and varied thermal conditioning needs, the extensive and expanding use of electronic medical equipment, disinfection and other special processes, and the life-safety imperative of uninterrupted building operations.
Outpatient surgery centers, skilled nursing facilities, and clinics share some of these challenges and are increasingly being used to provide care once reserved for inpatient hospitals.
Benchmarking is an assessment approach in which energy-related metrics measured or estimated at one facility are compared to those from other facilities and/or specific performance targets. Benchmarks can be derived from distributions of metric values obtained from facilities having similar functionality or characteristics, from engineering analysis or building simulation modeling, or from expert knowledge of standard and best practices. Energy benchmarking allows building owners, managers, and facilities engineers and managers to view how their energy use compares to that of their “peer buildings” (buildings similar in size, function, or another service metric). Based on the performance of an individual building relative to the benchmark, facilities managers can identify potential best practices at their facility (e.g., where they perform better than the benchmark) as well as areas for improvement (e.g., where they perform worse than the benchmark).
The research team at LBNL developed an energy benchmarking system for hospitals to provide information to better understand hospitals’ energy performance and identify energy savings opportunities. While many benchmarks begin with information available from utility bills, the LBNL benchmark works with more resolved energy use data. Singer (2009) presents Version 1.0 of the Hospital Energy Benchmark
This benchmarking system is designed to understand energy use through metrics associated with the following major building energy services and systems:
- Cooling (including space and equipment)
- Space heating
- Domestic hot water (DHW)
- Ventilation (air movement)
- Miscellaneous equipment and plug loads (including distributed medical equipment and computers).
Additionally considered are the following services and spatial resolutions of specific relevance to hospitals:
- Large (“Group I”) medical equipment.
- Patient room areas.
- Other large, resolvable loads (e.g. data centers, kitchens), as feasible.
Energy Efficiency Roadmap
The Energy Efficiency Roadmap presents a road map for improving the energy efficiency of hospitals and other healthcare facilities. The report compiles input from a broad array of experts in healthcare facility design and operations. The initial section lists challenges and barriers to efficiency improvements in healthcare (see below). Achieving energy efficiency will require a broad set of activities including research, development, deployment, demonstration, training, etc., organized around 48 specific objectives. Specific activities are prioritized in consideration of potential impact, likelihood of near- or mid-term feasibility and anticipated cost-effectiveness. This document is intended to be broad in consideration though not exhaustive. Opportunities and needs are identified and described with the goal of focusing efforts and resources.
- Challenges related to the provision of medical services: Many parts of a hospital must be operational 24 hours a day, 365 days a year, making it difficult to apply some of the same energy management strategies that have been successful in other environments. Hospitals also have larger HVAC energy use than other commercial buildings, due to stricter ventilation and filtration requirements (an infection control measure). Further, hospitals have unique electric loads (e.g., medical equipment), may need to operate “off the grid,” requiring additional power supplies (e.g., generators), and are often designed for future flexibility.
- Challenges related to healthcare organization, structure, and culture: The major mission of hospitals is healthcare. Given that energy costs represent a small fraction of operation costs (usually <5%), hospitals are typically built with limited capital, and most hospitals need to cut costs, which means energy-efficiency measures compete with other capital investments.
- Challenges related to the legacy of current facility stock: Hospital buildings between 50-100 years old will be responsible for most US hospital energy use over the next two decades. Construction in an existing facility (e.g., a new wing, a retrofit, etc.) is an infection risk and may trigger more extensive upgrades to meet newer codes, thus it may be more effective to concentrate on how to save energy in these buildings through energy-efficient operations that require minimal, if any, retrofit.
- Challenges related to codes and standards: Hospitals often need to meet stricter structural and HVAC provisions than other commercial buildings, making some energy-efficiency strategies (e.g., natural ventilation) more difficult to design and permit.
- Understand and Benchmark Energy Use: Develop standard performance metrics, begin to collect data for these metrics, and thus advance performance benchmarking. Energy monitoring and management system best practices should also be documented.
- Best Practices and Training: Document best practices and provide training in their implementation to hospital designers, operators, and facility engineers. Specifically, provide guidance for commissioning, information on energy performance of building products, improved maintenance, and strategies to reduce reheat through HVAC system management.
- Codes and Standards: Develop performance-based criteria for ventilation standards and research the effect of mixed mode ventilation on medical outcomes.
- HVAC System Design (Utilization of Existing Technologies): Assess various HVAC systems, and document performance evaluations of these and other energy-related design elements. Develop guidance documents for designs that minimize reheat and use alternative HVAC systems, including 100% outside air systems, and displacement ventilation systems, among others.,
- HVAC Technology and Design Innovation: Demonstrate energy-efficient HVAC technologies and equipment, including alternative dehumidification systems, chilled beam cooling, air filtration and cleaning systems, and others, through test bed facilities.
- Electrical System Design: Design electrical systems that support efficient sub-metering and on-site renewable and co-generation power sources, and work to improve the efficiency of distribution systems.
- Lighting: Implement lighting best practices, including lighting controls and utilization of daylight.
- Medical Equipment and Process Loads: Document the energy use and operational patterns of stationary and distributed medical equipment to inform an energy-efficiency rating system. Also, document process loads in hospitals to better understand the impact of medical equipment on these loads.
- Economic and Organizational Issues: Develop design tools to evaluate cost and energy implications of efficiency improvements as a means of motivating efficiency investment. Simultaneously, develop strategies to overcome structural challenges to efficiency investment.
- Designing Sustainable Hospitals: Document the effects of building form on patient outcomes and use human factors engineering to illustrate the benefits of sustainable hospital design.
Efforts to improve energy efficiency in hospitals can be aided by an accurate apportionment of energy use by building service. Distinct and clearly identifiable end-uses include space cooling, space heating, ventilation (fan energy), lighting, domestic water heating, and steam for sterilization and humidification. There is substantial interest and much uncertainty about the contribution of medical equipment and other miscellaneous electric loads (MELs) to overall energy use in hospitals. This project aims to develop methodologies to assess and quantify these loads and to advance understanding of their magnitude.
It is important to first define the loads that are being examined in this study. The term “medical equipment” is commonly used to describe devices or instruments that contribute to patient care e.g., through diagnosis or treatment. Medical equipment is categorized into three groups. Group I comprises high-voltage imaging devices (e.g., X-rays, MRIS) that are typically stationary and may include multiple components installed in a designated facility. Group II is major moveable equipment that requires special utilities (e.g., patient monitors, EKGs). Group II devices may be the major power users in a hospital because they draw moderate levels of power, but they operate often. Minor medical equipment, also referred to as distributed equipment, includes battery-operated equipment, like IV pumps. EPRI suggests a different classification system, classifying equipment based on function rather than power draw. EPRI groups equipment into eight categories: (1) Patient monitoring, (2) Diagnostic, (3) Medical imaging systems (largest single load type), (4) X-ray, (5) Surgical, (6) Therapeutic, (7) Life-support, and (8) Laboratory equipment. Our study focuses on Group II and Minor Movable equipment, and includes primarily patient monitoring, diagnostic, therapeutic, and life-support equipment. Where possible, we consider surgical and laboratory equipment.
In addition to devices with uniquely medical purposes, there are more common appliances and other equipment that serve medical functions. These include refrigerators, microwaves, computers, etc. There also are many electrically-powered devices that are not directly used in medical care but contribute to overall power use. These include vending machines, televisions, water fountain chillers, etc. The total power consumption of miscellaneous electrical loads includes both medical equipment and devices without clear medical purposes.
Framework for Quantifying Medical Equipment Energy Use
Data and Tools for Building Energy Use
- AHA TrendWatch
- AHA Chartbook
- Commercial Building Energy Consumption Survey (CBECS)
- California Commercial End-Use Survey (CEUS)
- Energy IQ for system-level benchmarking (includes CBECS and CEUS data)
- Cal-Arch benchmarking tool
- EPA Healthcare Benchmarking Tool (Portfolio Manager for facility-level benchmarking)
American Hospital Association (AHA)
American College of Healthcare Executives (ACHE)
American Institute of Architects (AIA)
American Society for Healthcare Engineering (ASHE)
American Society of Heating Refrigerating and Air-Conditioning Engineers (ASHRAE)
California Society for Healthcare Engineering (CSHE)
Illuminating Engineering Society of North America (IESNA)
International Facility Management Association (IFMA)
Department of Energy (DOE)
Hospital Energy Alliance
Environmental Protection Agency
ENERGYSTAR for Healthcare
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