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A long-term field study recording domestic hot water (DHW) consumption in households was used to tune a load profile generator. The methodology used in this load profile generator is also applicable to electric loads in distribution grids. Accurate DHW load profiles are essential to estimate the performance of renewable energy systems. One day and long-term randomly generated DHW profiles are useful for simulation, sizing and optimization of components in solar hot water installations such as storage tank, heat exchanger, collector area and additional heater. This work is also relevant to create standards for product testing and certification. DHW usage and draw off patterns are geographically dependent, so recent and local measurements are required to tune models and create accurate load profiles. Measurements show that DHW consumption is very volatile. The daily average value varies from 20 to 40 Litres per person (60 °C outlet temperature). The profiles underlie some trends (predominantly consumption in the morning or in the evening or spread over the day). The DHW consumption in Switzerland follows similar patterns observed in other countries, such as no significant decrease in 2 consumption during weekends, and no strong correlation with weather conditions neither outdoor temperature nor rain.

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Objective: The aim was to assess the impact of operating room (OR) ventilation quality on surgical site infections (SSIs) using a novel ventilation index. Background: Previous studies compared laminar air flow with conventional ventilation, thereby ignoring many parameters that influence air flow properties. Methods: In this cohort study, we surveyed hospitals participating in the Swiss SSI surveillance and calculated a ventilation index for their ORs, with higher values reflecting less turbulent air displacement. For procedures captured between January 2017 and December 2019, we studied the association between ventilation index and SSI rates using linear regression (hospital-level analysis) and with the individual SSI risk using generalized linear mixed-effects models (patient-level analysis). Results: We included 47 hospitals (182 ORs). Among the 163,740 included procedures, 6791 SSIs were identified. In hospital-level analyses, a 5-unit increase in the ventilation index was associated with lower SSI rates for knee and hip arthroplasty (−0.41 infections per 100 procedures, 95% confidence interval: −0.69 to −0.13), cardiac (−0.89, −1.91 to 0.12), and spine surgeries (−1.15, −2.56 to 0.26). Similarly, patient-level analyses showed a lower SSI risk with each 5-unit increase in ventilation index (adjusted odds ratio 0.71, confidence interval: 0.58-0.87 for knee and hip; 0.72, 0.49-1.06 for spine; 0.82, 0.69-0.98 for cardiac surgery). Higher index values were mainly associated with a lower risk for superficial and deep incisional SSIs. Conclusions: Better ventilation properties, assessed with our ventilation index, are associated with lower rates of superficial and deep incisional SSIs in orthopedic and cardiac procedures. OR ventilation quality appeared to be less relevant for other surgery types.