Medical Office Building Research Articles

Investigation of HVAC operation strategies for office buildings during COVID-19 pandemic

To minimize the indoor transmission of contaminants, such as the virus that can lead to COVID-19, buildings must provide the best indoor air quality possible. Improving indoor air quality can be achieved through the building’s HVAC system to decrease any concentration of indoor contaminants by dilution and/or by source removal. However, doing so has practical downsides on the HVAC operation that are not always quantified in the literature. This paper develops a temporal simulation capability that is used to investigate the indoor virus concentration and operational cost of an HVAC system for two mitigation strategies: (1) supplying 100% outdoor air into the building and (2) using different HVAC filters, including MERV 10, MERV 13, and HEPA filters. These strategies are applied to a hypothetical medium office building consisting of five occupied zones and located in a cold and dry climate. We modeled the building using the Modelica Buildings library and developed new models for HVAC filtration and virus transmission to evaluate COVID-19 scenarios. We show that the ASHRAE-recommended MERV 13 filtration reduces the average virus concentration by about 10% when compared to MERV 10 filtration, with an increase in site energy consumption of about 3%. In contrast, the use of 100% outdoor air reduces the average indoor concentration by about an additional 1% compared to MERV 13 filtration, but significantly increases heating energy consumption. Use of HEPA filtration increases the average indoor concentration and energy consumption compared to MERV 13 filtration due to the high resistance of the HEPA filter.

The effect of building retrofit measures on CO2 emission reduction – A case study with U.S. medium office buildings

Building retrofits have great potential to reduce CO2 emissions since buildings are responsible for 36% of emissions in the United States. Several existing studies have examined the effect of building retrofit measures on CO2 emission reduction. However, these studies oversimplified emission factors of electricity by adopting constant annual emission factors. This study uses hourly emission factors of electricity to analyze the effect of building retrofit measures on emission reduction using U.S. medium office buildings as an example. We analyzed the CO2 emission reduction effects of eight building retrofit measures that related to envelope and mechanical systems in five locations: Tampa, San Diego, Denver, Great Falls, and International Falls. The main findings are: (1) estimating CO2 emission reduction with constant emission factors overestimates the emission reduction for most measures in San Diego, while it underestimates the emission reduction for most measures in Denver and International Falls; (2) The same retrofit measure may have different effects on CO2 emission reduction depending on the climate. For instance, improving lighting efficiency and improving equipment efficiency have less impact in emission reduction in cold climates than hot climates; and (3) The most energy efficient measure may not be the most efficient emission measure. For example, in Great Falls, the most energy efficient measure is improving equipment efficiency, but the most efficient emission measure is improving heating efficiency.

A holistic fault impact analysis of the high-performance sequences of operation for HVAC systems: Modelica-based case study in a medium-office building

ASHRAE Guideline 36: High-performance sequences of operation (SOO) for Heating, Ventilation, and Air-conditioning (HVAC) Systems has been demonstrated to save 17%-30% energy under ideal simulation environments. However, HVAC systems are susceptible to various types of faults in a real building operation. There are no existing studies that pertain to a comprehensive fault impact analysis of the high-performance control sequences suggested by ASHRAE Guideline 36 for HVAC systems. How these sequences handle and adapt to the various types of faults is still largely unknown. In this context, a comprehensive fault impact analysis and robustness assessment of the high-performance control sequences is conducted. A Modelica-based medium office virtual testbed is developed following the air-side and the plant-side SOO. A total of 359 fault scenarios in three different seasonal operating conditions (cooling, shoulder, and heating seasons) are injected into the baseline model. The evaluated key performance indexes (KPIs) include the operational cost, source energy, site energy, control loop quality, thermal comfort, ventilation, and power system metrics. The faults of the most negative impact are identified for different seasonal operating conditions over all the KPIs. The results also show that high-performance control sequences are well adapted for the vast majority (∼90%) of all the fault scenarios over all the KPIs in this study.

Acoustical Conformance with FGI for Tenant Improvements in Outpatient, Medical Office or Clinic Facility Sound Isolation/Privacy Design

Acoustical privacy and noise control design and implementation guidance is needed, regarding Facility Guidelines Institute (FGI) criteria for outpatient medical facilty tenant improvements (TI). TI in existing commercial buildings or medical office buildings may not have capital budgets or expected facility/lease life that hospitals enjoy. Full conformance to FGI criteria and guidelines may be limited; by economic feasibility and by constructability. Design professionals can use "good practice" space planning, demising assembly selection, and electronic sound masking to achieve appropriate acoustical privacy within reasonable capital expense budgets. Consider FGI criteria for demising partition, ceiling, door and window selections plus infrastructure equipment and material selections that can provide cost-effective lightweight, common construction standards. The objectives are to protect the privacy of patient information and provide quiet spaces, free of transient disturbance for clear speech communications. Continuous ambient sound increases speech privacy including speech transmitted from enclosed quiet spaces. Criteria for acoustics, speech privacy,continuous noise and masking exists in FGI. Temporal level changes (on/off, transients) and tonality (spectrum smoothness or balance) should be considered in basis-of-design (BoD). This paper will present design guidelines for selecting demising assemblies and supplemental sound masking for outpatient clinical spaces in commercial or medical office buildings.

Biomimetic adaptive electrochromic windows for enhancing building energy efficiency

The concept of bioinspiration, which is a new design paradigm inspired by solutions found in biological systems, has led to many innovative designs in different fields in recent years. This study presents the design of biomimetic adaptive façade (BAF) to enhance the energy efficiency of buildings, which approximately accounts for 40% of the global energy consumption. A comprehensive analysis was conducted to identify the similarities between the mechanism of electrochromic window and chameleon’s skin. From that, the design of the BAF system was proposed based on the bioinspired analogy. In addition, a building energy modeling software (EnergyPlus), a Python package (Eppy toolkit), and a decision-making assistance tool were integrated into a computational tool to support the design and evaluate the feasibility of BAF systems. A medium office building was used as a case study to validate the capability of the proposed approach for two weather conditions in Melbourne, Australia, and Texas, United State. The results show that the proposed BAF can reduce energy consumption by 9.3–23.5% and 14.6–19.6% for Melbourne and Texas, respectively, compared to the benchmarking facades. The effect of window-to-wall ratio and orientation of the BAF system on the energy-efficiency and cost-efficiency of buildings were also investigated. The results confirm the potential of BAF in improving building energy efficiency.

Creating a Dedicated Pandemic Ambulatory Clinic: Lessons Learned From COVID-19.

Background and Objectives:COVID-19 is highly infectious and the pandemic requires many adaptations to how we deliver medical care. Early in the pandemic, much of this focus was on hospital and emergency department care delivery models to ensure the safety of non–COVID-19 patients and health care workers. However, providing much needed outpatient assessments for COVID-19 patients during a pandemic is also fraught with challenges. From our review of the literature, best practices for a dedicated pandemic ambulatory outpatient clinic have not previously been described. We present a model for creating a dedicated ambulatory pandemic clinic at our institution for the acute care needs of COVID-19 patients.Methods:To address the current pandemic, the Mayo Acute Symptoms of COVID-19 Clinic was implemented on April 13, 2020, with the aims of providing a stand-alone location for COVID-19 patients to have acute outpatient evaluations as well as diagnostics.Results:Recognized challenges addressed included consideration of airflow recirculation patterns in standard medical office buildings, optimization of protocols to conserve personal protective equipment (PPE), limiting total exposure time during patient flow, and reducing surfaces and spaces that patients would physically contact. To this end, unique methods of patient scheduling, patient flow process, staff training, and PPE protocols were developed and are explained in detail in this article.Conclusion:In the COVID-19 pandemic, as well as inevitably in future pandemics, outpatient medical facilities need to be prepared to care for nonhospitalized and nonemergent pandemic patients. We offer a practical approach that has been successful at our institution, with opportunity for local adaptation based on need and resources.

What are the impacts on the HVAC system when it provides frequency regulation? – A comprehensive case study with a Multi-Zone variable air volume (VAV) system

Heating, ventilation, and air-conditioning (HVAC) systems in commercial buildings have proven to be a great asset for providing secondary frequency regulation (FR) service to the power grid. However, how the provision of FR service affects the HVAC system performance is still largely unknown. This paper investigates how a HVAC system performance and its associated controls are impacted during and after a FR service. We exploit a dynamic Modelica-based medium office building model as a virtual testbed with the Air Handling Unit (AHU) fans providing the FR service for the assessment. The virtual testbed adopts state-of-the-art HVAC control sequences and an experimentally validated frequency regulation control scheme. The comprehensive study of 832 case studies considers several scenarios, consisting of different regulation capacities (demand levels), standardized FR test signals, and building load profiles in 16 U.S, climate zones. The holistic assessment includes the interaction between the FR and the HVAC baseline controls, the impact of FR on the occupant’s thermal comfort, and, more importantly, the energy efficiency.The results show that FR has little or no impact on the HVAC operation and occupant thermal comfort while the building is providing the service if an appropriate regulation capacity is pre-determined. However, if the regulation capacity is overestimated, the quality of the FR service provided by the HVAC system and the HVAC energy efficiency will be affected due to the equipment operating constraints. In addition, the AHU supply air temperature fluctuates, and the controller cannot maintain the desired setpoint as the FR magnitude is increased. After the FR service time, the system takes a certain period to return to normal operation. The rebound period extends with the increase in the FR magnitude. For this case study, there exists a control conflict between the FR control and the existing HVAC control (from ASHRAE Guideline 36-2018) during high load conditions, causing the fan speed to saturate. The increased fan electricity consumption caused by this control conflict will offset the potential revenue a building can earn from offering the FR service. In addition, the rebound power usage could have a negative effect on the grid.

Evaluating the energy impact potential of energy efficiency measures for retrofit applications: A case study with U.S. medium office buildings

Quantifying the energy savings of various energy efficiency measures (EEMs) for an energy retrofit project often necessitates an energy audit and detailed whole building energy modeling to evaluate the EEMs; however, this is often cost-prohibitive for small and medium buildings. In order to provide a defined guideline for projects with assumed common baseline characteristics, this paper applies a sensitivity analysis method to evaluate the impact of individual EEMs and groups these into packages to produce deep energy savings for a sample prototype medium office building across 15 climate zones in the United States. We start with one baseline model for each climate zone and nine candidate EEMs with a range of efficiency levels for each EEM. Three energy performance indicators (EPIs) are defined, which are annual electricity use intensity, annual natural gas use intensity, and annual energy cost. Then, a Standard Regression Coefficient (SRC) sensitivity analysis method is applied to determine the sensitivity of each EEM with respect to the three EPIs, and the relative sensitivity of all EEMs are calculated to evaluate their energy impacts. For the selected range of efficiency levels, the results indicate that the EEMs with higher energy impacts (i.e., higher sensitivity) in most climate zones are high-performance windows, reduced interior lighting power, and reduced interior plug and process loads. However, the sensitivity of the EEMs also vary by climate zone and EPI; for example, improved opaque envelope insulation and efficiency of cooling and heating systems are found to have a high energy impact in cold and hot climates.

Introduction Example of DC Powered Lighting System for Medium Office Building

Introduction Example of DC Powered Lighting System for Medium Office Building

Distortions in a segment of the commercial office market: the case of medical office buildings

ABSTRACT This article examines the U.S. market for Medical Office Buildings (MOB), a segment of the office market that has received little attention in the academic literature. Our attention is directed towards the impact of Certificate-of-Need (CON), a set of state level distortionary public laws that regulate health services planning. With respect to real estate, we find CON regulations increase rents and sales prices medical office building (MOB) rental rates. What makes these findings particularly interesting is that none of the states that currently have CON legislation in place have any language restricting MOB development. The empirical findings suggest that there is a supply constraint due to CON that has a distortionary effect on the MOB market.

Speech privacy in healthcare: A case study discussion of design and measurement results

This presentation will be an overview of speech privacy design and measurement summary for a medical office building in Roseville, CA, where TEECOM provided the acoustical design services. Speech privacy can be analyzed in several ways. For this presentation, TEECOM will compare the measured speech privacy performance using Speech Privacy Predictor (SPP) and Speech Privacy Class (SPC) for partitions between exam rooms and between offices as well as their respective door-walls. The project encountered budget constraints that limited the design options; demising walls were required to be partial-height. An electronic sound masking system was incorporated to elevate the ambient noise levels within comfortable limits to provide a controlled background noise level in the hallways and in enclosed spaces. Post-occupancy comments on the quality of speech privacy were gathered by the Architecture client and will be shared to support the quantifiable findings. Considerations for further improvements are described, including space planning and other design elements that can be used to achieve the confidentially goals and requirements established by HIPAA (Health Insurance Portability and Accountability Act).

Jacobs School of Medicine and Biomedical Sciences at University at Buffalo.

Jacobs School of Medicine and Biomedical Sciences at University at Buffalo.

Performance Simulation and Analysis of Occupancy-Based Control for Office Buildings with Variable-Air-Volume Systems

Variable-air-volume (VAV) systems are used in many office buildings. The minimum airflow rate setting of VAV terminal boxes has a significant impact on both energy consumption and indoor air quality. Conventional controls usually have the terminal’s minimum airflow rate at a constant (e.g., 30% or more of the terminal design airflow rate), irrespective of the occupancy status, which may cause problems, such as excessive simultaneous heating and cooling, under ventilation, and thermal comfort issues. This paper examines the potential of energy savings from occupancy-based controls (OBCs). The sensed occupancy information, either occupant presence or people count, is used to determine the airflow rate of terminal boxes, the thermostat setpoints, and the lighting control. Using EnergyPlus, a whole-building energy modeling software, the energy savings of OBC strategies are evaluated for representative existing medium office buildings in the U.S. The simulation results show that the conventional OBC, based on occupant presence sensing, can save 8% of whole-building energy use in Miami (hot climate) for systems without air-side economizer and about 13% in both Baltimore (mixed climate) and Chicago (cold climate). Comparatively, the advanced OBC, based on people counting, can save 8% in Miami to 23% in Baltimore for systems with economizers. The outdoor-air fraction of the supply air from air-handling units significantly affects the potential energy savings from the advanced OBC strategy. In addition to energy savings, the advanced OBC satisfies the zone ventilation during all occupied hours over the whole year.

How do electricity pricing programs impact the selection of energy efficiency measures? – A case study with U.S. Medium office buildings

Building owners usually select energy efficiency measures (EEMs) by referring to return on investment (ROI). Current studies tend to apply static energy price to estimate ROI. However, more and more buildings are adopting dynamic electricity pricing programs. To understand how electricity pricing programs impact the selection of EEMs, this paper presents an analysis of the ROIs of EEMs under different pricing programs using U.S. medium office buildings as an example. Eight EEMs in four typical cities are selected as case studies. Considering five electricity pricing programs scenarios (one static program and four dynamic programs), EEMs are selected based on their ROIs. The main findings are: (1) The ROIs of EEMs change under different pricing programs. (2) In Honolulu, Buffalo, and Denver, replacing interior fixtures with higher-efficiency fixtures has a significantly higher ROI than the rest EEMs under all five pricing programs. However, the ROI of this EEM in Honolulu ranges from 28% to 47% for different pricing programs. (3) Similarly, in Fairbanks, replace heating coil with higher-efficiency coil produce higher ROI than the rest under all five pricing programs. (4) For other EEMs, their ROI rankings vary according to electricity pricing programs.

The Implementation of Screening for Adverse Childhood Experiences in Pediatric Primary Care

To assess the implementation of screening, screening rates, and prevalence of adverse childhood experiences (ACEs) in a large integrated healthcare system. Kaiser Permanente Southern California is a large integrated healthcare system with 15 medical centers/hospitals and 233 medical office buildings that serve approximately 1.5 million children. Screening for ACEs began in July 2018 at 1 medical center (Downey, Bellflower medical office) for 3- and 5-year-old well-child visits (yearly physical examination). It quickly expanded to 3 other medical centers (6 clinics in total) and now also includes the 10- and 13-year-old well-child visits. Since July 2018 we have screened 3241 3-year-olds (53% of the target population), 2761 5-year-olds (53%), 545 10-year-olds (37%), and 509 13-year-olds (13%). Of the 3-year-olds who were screened, 15% had an ACEs score of 1 or higher. Of the 5-year-olds that were screened, 17.5% had an ACEs score of 1 or higher. Of the 10-year-olds, 30.5% had an ACEs score of 1 or higher and of the 13-year-olds, 33.8% had an ACEs score of 1 or higher. Although we have encountered some challenges, particularly with follow-up for those screeningpositive for ACEs, screening was feasible. The data show an increasing trend of ACEs in 3- to 13-year-old children, highlighting the need for early education about ACEs to mitigate the effects of toxic stress.

Development of new baseline models for U.S. medium office buildings based on commercial buildings energy consumption survey data

Building energy estimation for the building sector under various scenarios are needed for building energy regulation and policy making. This often starts with representative baselines (either empirical baseline or modeled baseline). Commercial Buildings Energy Consumption Survey (CBECS) data is a widely used empirical baseline for U.S. commercial buildings, but none of the existing baseline model are developed to represent the CBECS data. This paper aims to develop new baseline models for the U.S. medium office buildings, which can produce modeled baselines consistent with the CBECS data. First, we introduced the methodology to create baseline models and the criteria to evaluate the performance of baseline models. The methodology consists of three phases: (1) identification of model inputs, (2) model calibration, and (3) model validation with uncertainty analysis. The evaluation index is the coefficient of variation of the root-mean-square deviation (CV(RMSD)) of site energy use intensities (EUIs) between the modeled baseline and empirical baseline. Then 30 new baseline models for two vintages (pre- and post-1980) and 15 climate zones were created. The evaluation shows that the CV(RMSD) is lower than 0.05 for the modeled baselines produced by the new baseline models. As a comparison, the CV(RMSD) is higher than 0.1 for the existing modeled baselines generated by DOE Commercial Reference Building Models. Further analysis shows that the new baseline models are able to capture the uncertainties of the representative features of existing buildings.

Enhancing building energy efficiency by adaptive façade: A computational optimization approach

The energy consumption in buildings, which accounts for approximately one-third of the total energy used in the world, can be reduced significantly by employing adaptive façades. In this study, a computational optimization approach is proposed to enhance the energy efficiency of buildings based on the design of an adaptive façade system, which can adapt its thermal and visible transmittance for dynamically varying climatic conditions. The engine of the adaptive façade design approach is an automated optimization process, which combines the building energy simulation program (EnergyPlus) with an optimization technique through Eppy, a powerful Python toolkit. The modified firefly algorithm, an in-house optimization tool, is employed to design the adaptive façade system in this study. However, our proposed method is not tied to any particular optimization tool and does not impose any restrictions on a type of building. To this end, the capability of the proposed method for enhancing building energy efficiency is validated by two case studies, namely a typical single office room and a medium office building. We found that the proposed adaptive façade system can reduce the energy consumption by 14.9–29.0% and 14.2–22.3% for the first and second case study, respectively, compared to the static façades. These significant findings demonstrate the potential of adaptive façades to enhance the energy efficiency of buildings.

Potential benefits of cool walls on residential and commercial buildings across California and the United States: Conserving energy, saving money, and reducing emission of greenhouse gases and air pollutants

Solar-reflective “cool” walls reduce absorption of sunlight by the building envelope, which may decrease cooling load in warm weather and increase heating load in cool weather. Changes to annual heating, ventilation, and air conditioning (HVAC) energy use depend on climate, wall construction, wall orientation, building geometry, HVAC efficiency, and operating schedule. Changes to annual energy cost and energy-related emissions further vary with local energy prices and emission factors. We used EnergyPlus to perform over 100,000 whole-building energy simulations, spanning 10 different building categories, three building vintages, 16 California climate zones, and 15 United States (U.S.) climate zones.Cool walls yielded annual source energy, energy cost, and emission savings in all California climate zones and in warm U.S. (ASHRAE) climate zones. In California, annual whole-building HVAC energy cost savings were 4.0–27% in single-family homes, 0.5–3.8% in medium office buildings, and 0.0–8.5% in stand-alone retail stores. In warm U.S. climates—zones 1A (Miami, FL) through 4B (Albuquerque, NM)—annual HVAC energy cost savings were 1.8–8.3% in single-family homes, 0.3–4.6% in medium office buildings, and 0.5–11% in stand-alone retail stores. California and U.S. fractional source energy and emission savings were comparable to fractional energy cost savings. Per unit surface area modified, cool-wall savings often exceeded cool-roof savings because building codes typically prescribe much less wall insulation than roof insulation.

A Novel Design of Triple-Hybrid Absorption Radiant Building Cooling System With Desiccant Dehumidification

In air-conditioning, strategy of decoupling cooling and ventilation tasks has stimulated considerable interest in radiant cooling systems with dedicated outdoor air system (DOAS). In view of this, current paper presents a simulation study to describe energy saving potential of a solar, biogas, and electric heater powered hybrid vapor absorption chiller (VAC) based radiant cooling system with desiccant-coupled DOAS. A medium office building under warm and humid climatic condition is considered. To investigate the system under different operational strategies, energyplus simulations are done. In this study, a novel design involving solar collectors and biogas fired boiler is proposed for VAC and desiccant regeneration. Three systems are compared in terms of total electric energy consumption: conventional vapor compression chiller (VCC) based radiant cooling system with conventional VCC-DOAS, hybrid VAC-based radiant cooling system with conventional VCC-DOAS, and hybrid VAC-based radiant cooling system with desiccant-assisted VCC-DOAS. The hybrid VAC radiant cooling system and desiccant-assisted VCC-DOAS yields in 9.1% lesser energy consumption than that of the VAC radiant cooling system with conventional VCC-DOAS. Results also show that up to 13.2% energy savings can be ensured through triple-hybrid VAC radiant cooling system and desiccant-assisted VCC-DOAS as compared to that of the conventional VCC-based radiant system. The return on investment is observed to be 14.59 yr for the proposed system.

건물 에너지 모델링을 통한 오피스 건물의 지열 VRF 시스템의 에너지 성능 평가

건물 에너지 모델링을 통한 오피스 건물의 지열 VRF 시스템의 에너지 성능 평가