Optimizing Radiant Systems for Energy Efficiency and Comfort

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-energy buildings. Despite this growth, completed installations to date have demonstrated that controls and operation of radiant systems can be challenging due to a lack of familiarity within the heating, ventilation, and air-conditioning (HVAC) design and operations professions, often involving new concepts (particularly related to the slow response in high thermal mass radiant systems). To achieve the significant reductions in building energy use proposed by California Public Utilities Commission’s (CPUC’s) Energy Efficiency Strategic Plan that all new non-residential buildings be ZNE by 2030, it is critical that new technologies that will play a major role in reaching this goal be applied in an effective manner. This final report describes the results of a comprehensive multi-faceted research project that was undertaken to address these needed enhancements to radiant technology by developing the following: (1) sizing and operation tools (currently unavailable on the market) to provide reliable methods to take full advantage of the radiant systems to provide improved energy performance while maintaining comfortable conditions, (2) energy, cost, and occupant comfort data to provide real world examples of energy efficient, affordable, and comfortable buildings using radiant systems, and (3) Title-24 and ASHRAE Standards advancements to enhance the building industry’s ability to achieve significant energy efficiency goals in California with radiant systems. The research team used a combination of full-scale fundamental laboratory experiments, whole-building energy simulations and simplified tool development, and detailed field studies and control demonstrations to assemble the new information, guidance and tools necessary to help the building industry achieve significant energy efficiency goals for radiant systems in California

High Quality Maize Centromere 10 Sequence Reveals Evidence of Frequent Recombination Events

The ancestral centromeres of maize contain long stretches of the tandemly arranged CentC repeat. The abundance of tandem DNA repeats and centromeric retrotransposons (CR) have presented a significant challenge to completely assembling centromeres using traditional sequencing methods. Here we report a nearly complete assembly of the 1.85 Mb maize centromere 10 from inbred B73 using PacBio technology and BACs from the reference genome project. The error rates estimated from overlapping BAC sequences are 7 x 10-6 and 5 x 10-5 for mismatches and indels, respectively. The number of gaps in the region covered by the reassembly was reduced from 140 in the reference genome to three. Three expressed genes are located between 92 and 477 kb of the inferred ancestral CentC cluster, which lies within the region of highest centromeric repeat density. The improved assembly increased the count of full-length centromeric retrotransposons from 5 to 55 and revealed a 22.7 kb segmental duplication that occurred approximately 121,000 years ago. Our analysis provides evidence of frequent recombination events in the form of partial retrotransposons, deletions within retrotransposons, chimeric retrotransposons, segmental duplications including higher order CentC repeats, a deleted CentC monomer, centromere-proximal inversions, and insertion of mitochondrial sequences. Double-strand DNA break (DSB) repair is the most plausible mechanism for these events and may be the major driver of centromere repeat evolution and diversity. This repair appears to be mediated by microhomology, suggesting that tandem repeats may have evolved to facilitate the repair of frequent DSBs in centromeres

Field evaluation of occupant satisfaction and energy performance in eight LEED-certified buildings using radiant systems

In this study, we present the results of a post-occupancy assessment on thermal comfort, indoor air quality, and acoustical quality from 568 occupant surveys in eight LEED-certified buildings with radiant heating and cooling systems, and trends in low-energy consuming buildings based on building characteristics, radiant design, and building operator interviews. This study follows-up on a quantitative assessment of 60 office buildings that found radiant and all-air buildings have equal satisfaction with indoor environmental quality, with a tendency for increased thermal satisfaction in radiant buildings. Our objective was to investigate reasons of comfort and discomfort in the radiant subset, and to relate these to building characteristics and operations strategies. Our analysis revealed that the primary sources of temperature dissatisfaction are lack of control over the thermal environment (both temperature and air movement) and slow system response, both of which were seen to be alleviated with fast-response adaptive opportunities such as operable windows and personal fans. There was no optimal radiant design or operation that maximized thermal comfort, and building operators were pleased with reduced repair and maintenance associated with radiant systems compared to all-air systems. Occupants reported low satisfaction with acoustics. This was primarily due to sound privacy issues in open offices which may be exacerbated by highly reflective surfaces common in radiant spaces. Indoor air quality satisfaction appears to be aligned with thermal comfort more than ventilation strategy, and buildings with low annual energy consumption take advantage of free cooling and avoid heating and cooling in the same day or same season

Correction: Use of IoT sensing and occupant surveys for determining the resilience of buildings to forest fire generated PM2.5.

[This corrects the article DOI: 10.1371/journal.pone.0223136.]

Use of IoT sensing and occupant surveys for determining the resilience of buildings to forest fire generated PM2.5

Wildfires and associated emissions of particulate matter pose significant environmental and health concerns. In this study we propose tools to evaluate building resilience to extreme episodes of outdoor particulate matter using a combination of indoor and outdoor IoT measurements, coupled with survey-based information of occupants’ perception and behaviour. We demonstrated the application of the tools on two buildings with different modes of ventilation during the Chico Camp fire event. We characterized the resilience of the buildings on different temporal and spatial scales using the well-established I/O ratio and a newly proposed E-index that evaluates indoor concentration in the context of adopted 24-hour exposure thresholds. Indoor PM2.5 concentration during the entire Chico Camp Fire event was 21 μg/m3 for 4th Street (Mechanically Ventilated) and 36 μg/m3 for Wurster Hall (Naturally Ventilated). The cumulative median I/O ratio during the fire event was 0.27 for 4th Street and 0.67 for Wurster Hall. Overall E-index for 4th Street was 0.82, suggesting that the whole building was resilient to outdoor air pollution while overall E-index was 1.69 for Wurster Hall suggesting that interventions are necessary. The survey revealed that occupant perception of workplace air quality aligns with measured PM2.5 in the two buildings. The results also highlight that a large portion of occupants wore face masks, even though the PM2.5 concentration was below WHO threshold level. The results of our study demonstrate the utility of the proposed IoT-enabled and survey tools to assess the degree of protection from air pollution of outdoor origin for a single building or across a portfolio of buildings. The proposed survey tool also provides direct links between the PM2.5 levels and occupants’ perception and behavior

Field Evaluation of Thermal and Acoustical Comfort in Eight North-American Buildings Using Embedded Radiant Systems

We performed a post-occupancy assessment based on 500 occupant surveys in eight buildings using embedded radiant heating and cooling systems. This study follows-up on a quantitative assessment of 60 office buildings that found radiant and all-air buildings have comparable temperature and acoustic satisfaction with a tendency for increased temperature satisfaction in radiant buildings. Our objective was to investigate reasons of comfort and discomfort in the radiant buildings, and to relate these to building characteristics and operations strategies. The primary sources of thermal discomfort are lack of control over the thermal environment (both temperature and air movement) and slow system response, both of which were seen to be alleviated with fast-response adaptive opportunities such as operable windows and personal fans. There was no optimal radiant design or operation that maximized thermal comfort, and building operators were pleased with reduced repair and maintenance associated with radiant systems compared to all-air systems. Occupants reported low satisfaction with acoustics. This was primarily due to sound privacy issues in open-plan offices which may be exacerbated by highly reflective surfaces common in radiant spaces

Comparison of mean radiant and air temperatures in mechanically-conditioned commercial buildings from over 200,000 field and laboratory measurements

We assessed the difference between mean radiant temperature ((t_r ) ̅) and air temperature (t_a) in conditioned office buildings to provide guidance on whether practitioners should separately measure (t_r ) ̅ or operative temperature to control heating and cooling systems. We used measurements from 48 office buildings in the ASHRAE Global Thermal Comfort Database, five field studies in radiant and all-air buildings, and five test conditions from a laboratory experiment, including both radiant and all-air spaces. Considering only the ASHRAE Global Thermal Comfort Database because it is the largest and most representative dataset, under typical office conditions, the median absolute difference (e.g., disregarding direction of the difference) between (t_r ) ̅ and t_a was 0.4 ℃ (with interquartile range = 0.4 ℃), and more specifically, the median difference shows that (t_r ) ̅ was 0.4 ℃ (with interquartile range = 0.4 °C) warmer than t_a. In the radiant cooled laboratory tests, (t_r ) ̅ was significantly (p<0.05) cooler than t_a (average difference -0.1 ℃) while in the all-air cooled laboratory tests (t_r ) ̅ was significantly (p<0.05) warmer than t_a (average difference +0.3 ℃). While these observations are significant, the effect sizes are negligible to small based on Cohen’s d and Spearman’s rho. These observations indicate that (t_r ) ̅ and t_a are typically closer in radiantly cooled spaces than in all-air cooled spaces. The results suggest that t_a measurements are sufficient to estimate (t_r ) ̅ under typical office conditions, and that separately measuring (t_r ) ̅ or operative temperature is not likely necessary to improve thermal comfort, especially in buildings with radiant systems. Furthermore, spatial and temporal variations in t_a can be greater than the difference between (t_r ) ̅ and t_a at any one location in a thermal zone, thus we expect that such variations have a greater impact on occupant thermal comfort than the differences between (t_r ) ̅ and t_a

The Helping Families Programme: A new parenting intervention for primary aged children with severe and persistent conduct problems

Background: Severe and persistent conduct problems in children during the primary school years are associated with school exclusion, increased risk of delinquency and early substance abuse. Method: Literature reviews and consultation with experts in the field were used to better understand the factors that contribute to severe and persistent conduct problems and to identify the principles and potential methods to be included in a new intervention. Results: Grounded in an ecological perspective, an innovative, multimodal intervention, the Helping Families Programme, has been developed. It uses a modular approach to systematically address parent behaviour, cognition and emotion across five key risk factor domains: parental mood and dysregulation; parent-child, family and school relationships; substance misuse; social support and networks; and managing life events and crises. Conclusion: Initial piloting of the Programme has offered early support for the potential value of the underlying principles and methods of the Programme. © 2010 The Authors. Child and Adolescent Mental Healt

The relationship between sociocultural pressure to be thin and body dissatisfaction in preadolescent girls

This study investigates the relationships among sociocultural pressures to be thin, internalisation of the thin ideal, social comparison, body mass index, and body dissatisfaction in young girls. One hundred and fifty-three 10–13 year old girls completed measures assessing sociocultural pressure to be thin, media exposure, body dissatisfaction, social comparison, and internalisation of the thin ideal. Although sociocultural factors, as a group, were significantly associated with internalisation of the thin ideal, perceived media pressure was the only sociocultural influence uniquely related to internalisation of the thin ideal. Perceived pressure to be thin delivered by the media was found to be associated with body dissatisfaction via internalisation of the thin ideal. The relationship between internalisation of the thin ideal and body dissatisfaction was also partially influenced by social comparison. Body mass was found to have a direct association with body dissatisfaction. A model incorporating the relationships among media pressure, internalisation of the thin ideal, social comparison, and body dissatisfaction is proposed