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Most US energy consumption occurs in buildings, with cooling demands anticipated to increase net building electricity use under warmer conditions. The electricity generation units that respond to this demand are major contributors to sulfur dioxide (SO2) and nitrogen oxides (NOx), both of which have direct impacts on public health, and contribute to the formation of secondary pollutants including ozone and fine particulate matter. This study quantifies temperature-driven changes in power plant emissions due to increased use of building air conditioning. We compare an ambient temperature baseline for the Eastern US to a model-calculated mid-century scenario with summer-average temperature increases ranging from 1 C to 5 C across the domain. We find a 7% increase in summer electricity demand and a 32% increase in non-coincident peak demand. Power sector modeling, assuming only limited changes to current generation resources, calculated a 16% increase in emissions of NOx and an 18% increase in emissions of SO2. There is a high level of regional variance in the response of building energy use to climate, and the response of emissions to associated demand. The East North Central census region exhibited the greatest sensitivity of energy demand and associated emissions to climate.

Air source variable refrigerant flow (VRF) systems are grabbing a greater share of the market in moderate climates. However, they are not widely implemented in cold climates because they typically lose capacity and efficiency at low ambient temperatures. To overcome this barrier, VRF systems may be supplemented by an additional heat source. Alternately, they can be upgraded to water or ground source systems that are not subject to ambient temperatures. While questions remain regarding how to select, design, and operate VRF systems in colder climates to achieve good energy performance and reduce capacity degradation, we have analyzed several strategies and share our conclusions and observations in this article.

Commissioning and retro-commissioning (RCx) are critical steps to ensure that a building performs at its best. But commissioning and RCx are truly effective only if their impacts last over time, which cannot be taken for granted. Here, Gunasingh et al took a deep dive into dozens of RCx projects in Illinois to determine long-term persistence of savings from RCx and what drives that persistence.

Hackel talks about automatic daylighting control, which is an energy-savings strategy used with increasing frequency in high performance building design. This type of control generally includes a photosensor that automatically dims or switches electric lighting to a lower energy state in response to natural daylight. Considerable effort is often expended on architectural and lighting design to bring in more natural light and give these systems high potential for performance.

Hybrid ground-source heat pump (HyGSHP) systems are growing more prevalent, but there continues to be a need for additional information on the design and operation of these systems. This project monitored three actual HyGSHP systems, both in heating-and cooling-dominated buildings, to benchmark (and improve where necessary) existing models and operational practices for these systems, and measure the cost effectiveness of these systems. Results demonstrate the cost-effectiveness of the general hybrid strategy, from a life-cycle standpoint, in comparison to other ground-source and conventional systems. Results also detail lessons learned in equipment sizing, control, and pumping design. Scott Hackel ASHRAE Member Amanda Pertzborn Student Member ASHRAE

Hybrid ground-coupled heat pump systems (HyGCHPs) couple conventional ground-coupled heat pump (GCHP) equipment with supplemental heat rejection or extraction systems. In cooling-dominated climates, the use of a supplemental heat-rejection system has been shown to significantly improve the economics of the system. However, the design and operation of HyGCHPs are more complex than GCHPs, and the interaction between the components, the building, and the ground are nonintuitive. A systematic and comprehensive optimization of HyGCHP systems is necessary in order to fully quantify and understand how they should be designed and what their true potential is. This paper describes a simulation study integrating a HyGCHP model with an optimization engine in order to identify the optimal system design (i.e., component sizes) and control strategy that minimizes the lifecycle cost (LCC) of the system for a range of different climates and building types. In addition, the sensitivity of the optimal design to various economic parameters and physical assumptions was studied. The results of the parametric study were used to develop general design guidelines that can be used to select an equipment configuration, size the equipment, and control the equipment for an optimally designed HyGCHP system.

Various types of cellular injection have become a popular and costly treatment option for patients with knee osteoarthritis despite a paucity of literature establishing relative efficacy to each other or corticosteroid injections. Here we aimed to identify the safety and efficacy of cell injections from autologous bone marrow aspirate concentrate, autologous adipose stromal vascular fraction and allogeneic human umbilical cord tissue-derived mesenchymal stromal cells, in comparison to corticosteroid injection (CSI). The study was a phase 2/3, four-arm parallel, multicenter, single-blind, randomized, controlled clinical trial with 480 patients with a diagnosis of knee osteoarthritis (Kellgren–Lawrence II–IV). Participants were randomized to the three different arms with a 3:1 distribution. Arm 1: autologous bone marrow aspirate concentrate ( n  = 120), CSI ( n  = 40); arm 2: umbilical cord tissue-derived mesenchymal stromal cells ( n  = 120), CSI ( n  = 40); arm 3: stromal vascular fraction ( n  = 120), CSI ( n  = 40). The co-primary endpoints were the visual analog scale pain score and Knee injury and Osteoarthritis Outcome Score pain score at 12 months versus baseline. Analyses of our primary endpoints, with 440 patients, revealed that at 1 year post injection, none of the three orthobiologic injections was superior to another, or to the CSI control. In addition, none of the four groups showed a significant change in magnetic resonance imaging osteoarthritis score compared to baseline. No procedure-related serious adverse events were reported during the study period. In summary, this study shows that at 1 year post injection, there was no superior orthobiologic as compared to CSI for knee osteoarthritis. ClinicalTrials.gov Identifier: NCT03818737 The multicenter phase 3 trial of stem cell therapy for osteoarthritis (MILES) for knee pain revealed that cell therapies showed no significant difference in knee pain outcomes, compared to corticosteroid injections, 1 year following treatment.

SALVADORAN peace talks, set to resume in Mexico City today, are nearing what one diplomat calls the moment of truth.\"

WHEN Amanda Villatoro, one of eight trade unionists recently elected to serve in El Salvador's National Assembly, drives home from work, she clasps her steering wheel in one hand and a pistol in the other.