Large-Scale Modeling and DR Control of Electric Water Heaters With Energy Star and CTA-2045 Control Types in Distribution Power Systems

The paper proposes a generalized energy storage (GES) model for battery energy storage systems (BESS), electric water heaters (EWH) and heating, ventilation, and air-conditioning (HVAC) systems to enable demand response control complying to Energy Star and CTA-2045 standards. The demand response control has been implemented in the DER integration testbed, which was originally developed by EPRI, to demonstrate that the “energy content” and “energy take” for BESS and EWH with mixing valve technology are comparable for typical residential ratings. A distribution power system was modeled using the modified IEEE 123-bus feeder system, measured residential loads, and EWH power simulated based on realistic hot water draws from CBECC-Res software. The demand response control, which complies to CTA-2045 standards was implemented to the EWHs considering the energy take values. Results demonstrate that the EWHs can be controlled to postpone the peak power at the distribution system level and provide a large amount of energy storage, while maintaining system robustness. The impact on occupant comfort was also analyzed

Generalized Energy Storage Model-in-the-Loop Suitable for Energy Star and CTA-2045 Control Types

The paper proposes a generalized energy storage (GES) model for battery energy storage systems (BESS), electric water heaters (EWH) and heating, ventilation, and air-conditioning (HVAC) systems. The analogies, including state of charge versus water temperature differential, are identified and explained, and models-in-the-loop (MIL) are introduced, which are compatible with the Energy Star and CTA-2045 general specifications and command types. Emphasis is placed on the proposed EWH model as it needfully fulfills a gap in present literature. The corresponding MIL has been implemented in the DER integration testbed, which was originally developed by EPRI, and satisfactorily validated against experimental results. A case study is included to illustrate that the daily “energy content” and “energy take” for BESS and EWH with mixing valve technology are comparable for typical residential ratings. The BESS, which requires more initial investment, has advantages in terms of flexibility for contributing to grid services, which are illustrated through a combined simulation and experimental study based on data collected from a field demonstration site with four smart homes

Skeletal manifestations of juvenile hypothyroidism and the impact of treatment on skeletal system

Thyroid hormone mediates growth and development of the skeleton through its direct effects and through its permissive effects on growth hormone. The effect of hypothyroidism on bone is well described in congenital hypothyroidism, but the impact of thyroid hormone deficiency on a growing skeleton, as it happens with juvenile hypothyroidism, is less defined. In addition, the extent to which the skeletal defects of juvenile hypothyroidism revert on the replacement of thyroid hormone is not known. A study was undertaken in 29 juvenile autoimmune hypothyroid patients to study the skeletal manifestations of juvenile hypothyroidism and the impact of treatment of hypothyroidism on the skeletal system of juvenile patients. Hypothyroidism has a profound impact on the skeletal system and delayed bone age, dwarfism, and thickened bands at the metaphyseal ends being the most common findings. Post treatment, skeletal findings like delayed bone age and dwarfism improved significantly, but there were no significant changes in enlargement of sella, presence of wormian bones, epihyseal dysgenesis, vertebral changes and thickened band at the metaphyseal ends. With the treatment of hypothyroidism, there is an exuberant advancement of bone age, the catch up of bone age being approximately double of the chronological age advancement