Performance of a demand controlled mechanical extract ventilation system for dwellings

The main aim of ventilation is to guarantee a goodindoor air quality, related to the energy consumed forheating and fan(s). Active or passive heat recoverysystems seem to focus on the reduction of heatingconsumption at the expense of fan electricityconsumption and maintenance. In this study, demandcontrolledmechanical extract ventilation systems ofRenson (DCV1 and DCV2), based on natural supply inthe habitable rooms and mechanical extraction in thewet rooms (or even the bedrooms), was analysed forone year by means of multi-zone Contam simulationson a reference detached house and compared withstandard MEV and mechanical extract ventilationsystems with heat recovery (MVHR). To this end, IAQ, total energy consumption,CO2 emissions and total cost of the systems aredetermined. The results show that DCV systems withincreased supply air flow rates or direct mechanicalextract from bedrooms can significantly improve IAQ,while reducing total energy consumption comparedto MEV. Applying DCV reduces primary heatingenergy consumption and yearly fan electricityconsumption at most by 65% to 50% compared toMEV. Total operational energy costs and CO2emissions of DCV are similar when compared toMVHR. Total costs of DCV systems over 15 years aresmaller when compared to MVHR due to lowerinvestment and maintenance costs

Indoor Air Quality Design and Control in Low-Energy Residential Buildings, International Energy Agency, EBC Annex 68, Subtask 5 Final Report: Field measurements and case studies

IEA-EBC Annex 68: Indoor Air Quality Design and Control in Low Energy Residential Buildings investigates how to ensure that future low energy buildings are able to improve their energy performance while still providing comfortable and healthy indoor environments. More specifically, Subtask 5 of Annex 68 has dealt with generation of data for the verification of the models and strategies developed in the other Annex 68 Subtasks through controlled field tests and case study presentations

Observation of out-of-plane vibrations in few-layer graphene

We report the observation of layer breathing mode (LBM) vibrations in few-layer graphene (FLG) samples of thickness from 2 to 6 layers, exhibiting both Bernal (AB) and rhombohedral (ABC) stacking order. The LBM vibrations are identified using a Raman combination band lying around 1720 cm-1. From double resonance theory, we identify the feature as the LOZO' combination mode of the out-of-plane LBM (ZO') and the in-plane longitudinal optical mode (LO). The LOZO' Raman band is found to exhibit multiple peaks, with a unique line shape for each layer thickness and stacking order. These complex line shapes of the LOZO'-mode arise both from the material-dependent selection of different phonons in the double-resonance Raman process and from the detailed structure of the different branches of LBM in FLG.Comment: 17 pages, 7 figures, supplemental material include

Key findings of IEA EBC Annex 68 - Indoor Air Quality Design and Control in Low Energy Residential Buildings

The overall objective of the "Annex 68" Project, which belongs to the International Energy Agency's "Energy in Buildings and Communities" Implementing Agreement, has been to develop the fundamental basis for optimal design and control strategies for good Indoor Air Quality (IAQ) in highly energy efficient residential buildings, and to disseminate this information in a practically applicable guide. The strategies shall facilitate the possibility to design and operate residential buildings with minimal energy use, while ensuring impeccable indoor climates. The project completes its working phase by the end of spring 2019. The work has gathered laboratory and field data and developed new knowledge on pollution sources in buildings and how the transport mechanisms for the pollutants interact with heat, air and moisture conditions in materials and indoor zones. Furthermore, the project has assembled a set of contemporary models to simulate the combined heat, air, moisture and pollution conditions of buildings and their assemblies. The purpose has been to identify and describe amenable ways to optimize the provision of ventilation and air-conditioning. The paper gives an account of the project highlights

Spontaneous expulsion of three large fibroids after uterine artery embolization

Objective: To report a case of uneventful expulsion of huge fibroids after uterine artery embolization. Design: Case report. Setting: The Department of Obstetrics and Gynaecology of a university hospital. Patient(s): A 45-year-old woman who underwent uterine artery embolization for fibroids. Intervention(s): Transfemoral selective bilateral uterine artery catheterization and injection of 500–700 �m polyvinyl alcohol particles. Main Outcome Measure(s): Recovery of the patient. Result(s): The spontaneous expulsion of three fibroids on three different occasions over several months resulted in a significant reduction in menstrual loss and dysmenorrhea. Conclusion(s): Delivering fibroids or sections of fibroids may be a natural process after uterine artery embolization, therefore it is essential to warn women about the possible risk. Close follow-up is also essential. The size of the fibroids discharged did not require hysterectomy. Adequate antibiotic cover may be necessary to prevent sepsis