Determining the size of PHEV charging stations powered by commercial grid-integrated PV systems considering reactive power support

Due to low electricity rates at nighttime, home charging for electric vehicles (EVs) is conventionally favored. However, the recent tendency in support of daytime workplace charging that absorbs energy produced by solar photovoltaic (PV) panels appears to be the most promising solution to facilitating higher PV and EV penetration in the power grid. This paper studies optimal sizing of workplace charging stations considering probabilistic reactive power support for plug-in hybrid electric vehicles (PHEVs), which are powered by PV units in medium voltage (MV) commercial networks. In this study, analytical expressions are first presented to estimate the size of charging stations integrated with PV units with an objective of minimizing energy losses. These stations are capable of providing reactive power support to the main grid in addition to charging PHEVs while considering the probability of PV generation. The study is further extended to investigate the impact of time-varying voltage-dependent charging load models on PV penetration. The simulation results obtained on an 18-bus test distribution system show that various charging load models can produce dissimilar levels of PHEV and PV penetration. Particularly, the maximum energy loss and peak load reductions are achieved at 70.17% and 42.95% respectively for the mixed charging load model, where the system accommodates respective PHEV and PV penetration levels of 9.51% and 50%. The results of probabilistic voltage distributions are also thoroughly reported in the paper.

The effect of training in reduced energy density eating and food self-monitoring accuracy on weight loss maintenance

Background:
Failure to maintain weight losses in lifestyle change programs continues to be a major problem and warrants investigation of innovative approaches to weight control.
Objective:
The goal of this study was to compare two novel group interventions, both aimed at improving weight loss maintenance, with a control group.
Methods and Procedures:
A total of 103 women lost weight on a meal replacement–supplemented diet and were then randomized to one of three conditions for the 14-week maintenance phase: cognitive-behavioral treatment (CBT); CBT with an enhanced food monitoring accuracy (EFMA) program; or these two interventions plus a reduced energy density eating (REDE) program. Assessments were conducted periodically through an 18-month postintervention. Outcome measures included weight and self-reported dietary intake. Data were analyzed using completers only as well as baseline-carried-forward imputation.
Results:
Participants lost an average of 7.6 plusminus 2.6 kg during the weight loss phase and 1.8 plusminus 2.3 kg during the maintenance phase. Results do not suggest that the EFMA intervention was successful in improving food monitoring accuracy. The REDE group decreased the energy density (ED) of their diets more so than the other two groups. However, neither the REDE nor the EFMA condition showed any advantage in weight loss maintenance. All groups regained weight between 6- and 18-month follow-ups.
Discussion:
Although no incremental weight maintenance benefit was observed in the EFMA or EFMA + REDE groups, the improvement in the ED of the REDE group's diet, if shown to be sustainable in future studies, could have weight maintenance benefits.

Investigating energy and indoor environmental performance of aquatic centres

Aquatic centres are popular recreational facilities in Australia and other developed countries. These buildings have experienced exponential demand over the past few decades. The growing desire for better indoor environmental quality in aquatic centres has resulted in a marked increase in energy consumption in this sector. Community expectations in relation to aquatic centres are rising and these spaces are associated with wellness and health. Energy consumption in indoor swimming pool buildings is high due to the high indoor air temperatures, increased ventilation heat losses and the need to disinfect water. This study investigates the energy consumption and indoor environmental quality of seven aquatic centres in Australia. The construction and various energy consuming systems of the facilities are analysed and compared against the energy consumption. Thermal comfort data is collected through measuring the indoor environmental parameters. Building envelopes were found to be leaky in most of the buildings resulting in energy wastage. The main indicators for energy consumption were gross floor area, area of pool surface, and number of visitors. It was found that the set point temperatures were significantly high in some of the buildings resulting in high level of discomfort for the spectators and staff.