Development and application of test cases for comparing vertical ground heat exchanger models

The main objective of this paper is to establish a set of test cases for analytical verifications and intermodel comparisons of ground heat exchanger (GHX) models used in building simulation programs. Several test cases are suggested. They range from steady-state heat rejection in a single borehole to varying hourly loads with large yearly thermal imbalance in multiple borehole configurations. The usefulness of the proposed test cases is illustrated by running them with different GHX models. This comparison exercise has shown that 1-D models compare favourably well with the more elaborate 3-D models for relatively small simulation periods. The cyclic heat rejection/collection test has revealed some small deficiency in the load aggregation scheme of a particular model. Finally, the use of the asymmetric (cooling-dominated) load profile test case for a bore field composed of 100 boreholes revealed that the borehole wall temperature predicted by two GHX models can differ by as much as 10oC after a 30 year simulation

Dynamic Thermal Modeling of a Radiant Panels System and its Environment for Commissioning: Application to Case Study

As a part of a commissioning study, the cooling ceiling system of a large commercial building located in Belgium is evaluated. A representative office has been instrumented and data on the cooling ceiling system operating in real conditions have been collected. The simulation of the whole system is performed by means of a dynamic thermal model of the building and its HVAC system. The model considers the radiant panels as a dynamic-state finned heat exchanger connected to a simplified lumped dynamic model of the building. The behavior of the radiant ceiling system and the interactions with his environment (walls, ventilated façade, internal loads and ventilation system) has been experimentally and numerically evaluated. Commissioning test results show that the influence of surfaces temperatures inside the room, especially the façade, is considerable. Then, it is clear that the radiant ceiling system must be evaluated together with its designed environment and not as separate HVAC equipment

Evidence-based calibration of a building energy simulation model: Application to an office building in Belgium

Energy services play a growing role in the control of energy consumption and the improvement of energy efficiency in non-residential buildings. This work consists in the application of a simulation-based approach dedicated to whole-building energy use analysis for use in the frame of an energy efficiency service process. Focus is given to the calibration of a simplified dynamic hourly building energy simulation model by means of available energy use data and to the integration of the calibration process into the Energy Service Process. The developed simulation tool and the associated calibration method are applied to a real case study building located in Brussels, Belgium. The use of an evidence-based method ensures sticking to reality and avoids bad representation and hazardous adjustment of the parameters. Moreover, it is shown that the use of a sensitivity analysis method is of a great help to orient data collection and parameters adjustment processes

Dynamic Thermal Modeling of a Radiant Panels System and its Environment for Commissioning: Application to Case Study

As a part of a commissioning study, the cooling ceiling system of a large commercial building located in Belgium is evaluated. A representative office has been instrumented and data on the cooling ceiling system operating in real conditions have been collected. The simulation of the whole system is performed by means of a dynamic thermal model of the building and its HVAC system. The model considers the radiant panels as a dynamic-state finned heat exchanger connected to a simplified lumped dynamic model of the building. The behavior of the radiant ceiling system and the interactions with his environment (walls, ventilated façade, internal loads and ventilation system) has been experimentally and numerically evaluated. Commissioning test results show that the influence of surfaces temperatures inside the room, especially the façade, is considerable. Then, it is clear that the radiant ceiling system must be evaluated together with its designed environment and not as separate HVAC equipment

The first 110,593 COVID-19 patients hospitalised in Lombardy: a regionwide analysis of case characteristics, risk factors and clinical outcomes

Objectives: To describe the monthly distribution of COVID-19 hospitalisations, deaths and case-fatality rates (CFR) in Lombardy (Italy) throughout 2020. Methods: We analysed de-identified hospitalisation data comprising all COVID-19-related admissions from 1 February 2020 to 31 December 2020. The overall survival (OS) from time of first hospitalisation was estimated using the Kaplan-Meier method. We estimated monthly CFRs and performed Cox regression models to measure the effects of potential predictors on OS. Results: Hospitalisation and death peaks occurred in March and November 2020. Patients aged ≥70 years had an up to 180 times higher risk of dying compared to younger patients [70–80: HR 58.10 (39.14–86.22); 80–90: 106.68 (71.01–160.27); ≥90: 180.96 (118.80–275.64)]. Risk of death was higher in patients with one or more comorbidities [1: HR 1.27 (95% CI 1.20–1.35); 2: 1.44 (1.33–1.55); ≥3: 1.73 (1.58–1.90)] and in those with specific conditions (hypertension, diabetes). Conclusion: Our data sheds light on the Italian pandemic scenario, uncovering mechanisms and gaps at regional health system level and, on a larger scale, adding to the body of knowledge needed to inform effective health service planning, delivery, and preparedness in times of crisis

Simulation- Assisted Audit of an Air Conditioned Office Building

The case study presented here concerns the audit of a typical, medium-size, office building erected in Brussels at the end of the sixties. This building is equipped with a classical old fashioned air conditioning system composed of air handling units and four-pipes induction units. In the first part of the paper, a classical audit procedure is applied. It consists in a systematic analysis of all information available, with help of very simple calculation. In the second part of the paper, an equation-based building-HVAC simulation tool is used to assist the audit. Fuel and electricity consumption are then interpreted and significant energy saving opportunities are identified

Surveillance of Transmitted HIV-1 Drug Resistance in Gauteng and KwaZulu-Natal Provinces, South Africa, 2005-2009

Surveillance of human immunodeficiency virus type 1 transmitted drug resistance (TDR) was conducted among pregnant women in South Africa over a 5-year period after the initiation of a large national antiretroviral treatment program. Analysis of TDR data from 9 surveys conducted between 2005 and 2009 in 2 provinces of South Africa suggests that while TDR remains low (<5%) in Gauteng Province, it may be increasing in KwaZulu-Natal, with the most recent survey showing moderate (5%-15%) levels of resistance to the nonnucleoside reverse transcriptase inhibitor drug clas

The calibrated population resistance tool: standardized genotypic estimation of transmitted HIV-1 drug resistance

Summary: The calibrated population resistance (CPR) tool is a web-accessible program for performing standardized genotypic estimation of transmitted HIV-1 drug resistance. The program is linked to the Stanford HIV drug resistance database and can additionally perform viral genotyping and algorithmic estimation of resistance to specific antiretroviral drugs