Useful energy transfer in air-to-air heat recovery units in partly heated low energy buildings

In this study, the performance of ventilation systems with heat recovery in residential buildings with a low energy demand for heating was evaluated. In a completely heated building, the percentage of useful recovered heat will be equal to the nominal effectiveness of the heat exchanger. In the case some rooms are not heated, they will still receive preheated air. This part of the recovered heat will not directly increase comfort, so it does not completely contribute to the energy savings of the building. Simulations were done with TRNSYS to assess the percentage of usefully recovered heat. This value was found to be lower than the nominal effectiveness, but varying with several parameters

Performance assessment methods for boilers and heat pump systems in residential buildings

According to the European Commission, 40% of the total energy use belongs to the buildings sector. That corresponds to 36% of CO2 emissions in the European Union alone. Currently, HVAC systems are the major energy users in the building sector. Therefore, there is a necessity to assess the performance of different energy/comfort systems in buildings. However, finding a way to mitigate the performance gap between the calculated and real energy use in dwellings is of great importance. In Flanders, the Energy Performance and indoor climate regulation (EPB) dates back to 2006. Since the building context related to energy demand has changed significantly over the past years, investigation on how to evolve building energy assessment method framework in the EPB regulation in Flanders by dealing with the current issues will be indispensable. In 2017, new EN52000 series of standards have been published, containing extensive methods of assessing the overall energy performance of buildings. The main focus of this article is to analyze the assessment methods for the energy performance of boilers and heat pumps for residential appliance by comparing methodology stated in respected Energy performance and indoor climate regulation in Flanders (EPB), EcoDesign regulations and EN52000 standard series. The aim for future research is to determine the parameters that mostly influence the performance and in a next step compare the predicted performance to real energy use

Development of a dynamic model for ice-on-coil external melt storage systems

Ice storage systems are commonly used to balance the intermittency of renewable energy and decrease the peak load by switching to off-peak hours. An adequate model is necessary to predict the behaviour of these systems. However, there is a scarce in detailed models available used to describe the performance of an ice storage evaporator and its use in a refrigeration cycle. Most existing models approximate the working principles with a steady analysis, not considering the sub cooling of ice and thickness distribution along the length. The developed model in this article uses a discretisation in length and radial direction together with an adapted thermal resistance matrix method to limit the calculation time. It has a great variability of boundary conditions and the ability to implement different types of refrigerants. The simulation results are in good agreement with the data of the manufacturer. The model shows that switching from R404A to R449A reduces the total electricity consumption

Concentration and patterns of PAHs along the salinity gradient of the Scheldt estuary

At MUMM a method was recently developed to determine Polycyclic Aromatic Hydrocarbons (PAHs) in surface waters, even with high particulate matter concentrations, as is the case for the Scheldt Estuary. The method is based on a solid phase extraction with Bakerbond Speedisk C18 cartridges (Baker Inc, Phillipsburg, NJ). After testing this method during a one-year international OSPAR pilot study, the same method was applied for water samples collected for the ENDIS-RISKS program during 2003. Total water concentrations varied between 10 ng/L and 1200 ng/L. Concentrations are tight linked to sources. Fluoranthene was found in the highest concentrations near Antwerp, while in Doel acenaphtylene seemed to be the most dominant compound. The patterns were generally dominated by the lower molecule weight PAHs. There is a clear gradient from Antwerp to the mouth of the estuary near Flushing. Concentrations and PAH patterns were further compared to previous results

Endocrine disruptors in the Scheldt estuary (2)

The Scheldt Estuary is known as one of the more polluted estuaries in Europe (OSPAR, 2000). All major compartments of the estuary, i.e. water, suspended matter, sediments and biota, may be contaminated with chemicals such as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and organotin compounds. In the framework of the ENDIS-RISKS project, the different compartments of the estuary were sampled during the last 2 years and the concentration levels of 22 different polycyclic aromatic hydrocarbons (PAHs), 18 polybrominated diphenylethers (PBDEs), 5 OCPs, 16 PCBs and 6 organotin compounds were determined. For the biota, mysids were selected as indicator organism for this particular ecosystem. In this group of organisms, the highest contaminant levels were found for TBT with concentrations of up to 2500µg/kg on a dry weight basis (or approx. 100µg/kg on a wet weight basis). With an ecotoxicological assessment criterium (EAC) - as established by OSPAR - of 2.4µg/kg on wet weight basis, the EAC is exceeded by a factor of 50 at some sampling stations. For the same species, the body concentrations of SPCB7 varyied from 200 to 1400µg/kg (dry weight), again exceeding the OSPAR-EAC by a factor of more than 100. OCPs and PAHs are found in quantities varying from 5 to 100µg/kg (dry weight) which is below the EAC, except for lindane (EAC 0.29µg/kg on wet weight basis)

Endocrine disruptors in the Scheldt estuary: distribution exposure and effects

The Scheldt Estuary is known as one of the more polluted estuaries in Europe (OSPAR, 2000). The major compartments of the estuary, i.e. water, suspended solids, sediments and biota, are all affected by common POPs (persistent organic pollutants). In the framework of the ENDIS-RISKS project these compartments were frequently sampled during the last four years and analysed for these POPs indicated as possible endocrine disruptors. As such, the concentration levels of 22 different polycyclic aromatic hydrocarbons (PAHs), 18 polybrominated diphenylethers (PBDEs), 5 organochlorine pesticides (OCPs), 16 polychlorinated biphenyls (PCBs) and 6 organotin compounds e.g. TBT were determined by the MUMM laboratory. Their distribution (speciation within different compartments), concentration and geographic distribution are assessed. For the biota compartment, mysids were selected as an indicator organism for this particular ecosystem. In these invertebrates, the highest levels ever found for TBT were noted, with concentrations of up to 2500µg.kg-1 on a dry weight basis (or approx. 100µg.kg-1 on a wet weight basis). In the same species, SPCB7 levels varying from 200 to 1400 µg.kg-1 on dry weight were noted. OCPs and PAHs concentrations varied from 5 to 100µg.kg-1dw. The geographic distribution - along the salinity gradient of the Scheldt Estuary - of the body burdens of these compounds in mysids are discussed. Finally, the observations were compared to internationally accepted ‘Ecotoxicological Assessment Criteria’ used to assess the potential adverse effects on the ecosystem