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Abstract Dynamic modeling of HVAC system is extremely important for control analysis toward building energy saving. In order to provide researchers a simulation platform to analyze different control strategies, this paper introduces a simulation platform with customized Simulink block library based on dynamic HVAC component model. As an initiating effort, the current simulation platform is composed of basic modular HVAC components, including conduit, damper/valve, fan/pump, flow merge, flow split, heating coil, cooling coil, and zone. These modules are developed into Simulink customized blocks. The simulation platform is capable to calculate the flow rates of fresh air, exhaust air, and return air based on system characteristic and fan curve with customizable basic/advanced control strategies. A case study is proposed using single-zone, constant volume system by comparing the uncontrolled, fixed temperature and damper position controlled, and schedule based reset controlled cases. The simulation result proves that schedule based temperature and damper position reset has a significant impact on energy saving for both heating and cooling seasons. This simulation platform can be especially useful for analyzing the dynamic performance of different HVAC control strategies.

Abstract Dynamic modeling of HVAC system is extremely important for control analysis toward building energy saving. In order to provide researchers a simulation platform to analyze different control strategies, this paper introduces a simulation platform with customized Simulink block library based on dynamic HVAC component model. As an initiating effort, the current simulation platform is composed of basic modular HVAC components, including conduit, damper/valve, fan/pump, flow merge, flow split, heating coil, cooling coil, and zone. These modules are developed into Simulink customized blocks. The simulation platform is capable to calculate the flow rates of fresh air, exhaust air, and return air based on system characteristic and fan curve with customizable basic/advanced control strategies. A case study is proposed using single-zone, constant volume system by comparing the uncontrolled, fixed temperature and damper position controlled, and schedule based reset controlled cases. The simulation result proves that schedule based temperature and damper position reset has a significant impact on energy saving for both heating and cooling seasons. This simulation platform can be especially useful for analyzing the dynamic performance of different HVAC control strategies.

This study investigates the feasibility of a device to improve summer comfort in wood-frame houses using a Ventilated Internal Double Wall (VIDW). The idea is to increase the house's thermal inertia and to evacuate accumulated heat during the night with a mechanical ventilation system. The VIDW is a cooling wall. Numerous studies on night ventilation have been conducted, but the active ventilation inside the air gap of a double wall with high thermal inertia has not been studied. The first part of this study examines the impact of VIDWs on the thermal comfort in a timber-frame house. The VIDW is modeled in transient mode based on an electrical analogy with the assumption that the exchange coefficients are constant for a given air velocity. In addition, modeling a stationary CFD in forced convection of the VIDW air gap allowed us to study the cooling potential and the benefit of installing obstacles.

This study investigates the feasibility of a device to improve summer comfort in wood-frame houses using a Ventilated Internal Double Wall (VIDW). The idea is to increase the house's thermal inertia and to evacuate accumulated heat during the night with a mechanical ventilation system. The VIDW is a cooling wall. Numerous studies on night ventilation have been conducted, but the active ventilation inside the air gap of a double wall with high thermal inertia has not been studied. The first part of this study examines the impact of VIDWs on the thermal comfort in a timber-frame house. The VIDW is modeled in transient mode based on an electrical analogy with the assumption that the exchange coefficients are constant for a given air velocity. In addition, modeling a stationary CFD in forced convection of the VIDW air gap allowed us to study the cooling potential and the benefit of installing obstacles.

Abstract In this pilot study, a hitherto untapped source of fuel oil delivery data is explored as representative of a potentially powerful data source for analyses of residential oil consumption. The application of PRISM to oil data is studied in two parts: a detailed examination of a small number of houses, followed by an analysis of groups of houses in disparate (urban vs. suburban) regions. Extremely good fits to the data result, with interesting differences between houses with and without oil-fueled water heaters, and with some caveats regarding the interpretability of the results. The regional comparison shows almost no dependence on type of region or subset of houses. The most important finding is that monitoring consumption in oil-heated houses is almost as straightforward as it is in gas-heated houses, provided there are sufficient oil deliveries in the time period of interest.

Abstract In this pilot study, a hitherto untapped source of fuel oil delivery data is explored as representative of a potentially powerful data source for analyses of residential oil consumption. The application of PRISM to oil data is studied in two parts: a detailed examination of a small number of houses, followed by an analysis of groups of houses in disparate (urban vs. suburban) regions. Extremely good fits to the data result, with interesting differences between houses with and without oil-fueled water heaters, and with some caveats regarding the interpretability of the results. The regional comparison shows almost no dependence on type of region or subset of houses. The most important finding is that monitoring consumption in oil-heated houses is almost as straightforward as it is in gas-heated houses, provided there are sufficient oil deliveries in the time period of interest.

Abstract This paper explored the application of model predictive control (MPC) technology to the TBSs hybrid free cooling system with latent heat thermal energy storage (LHTES) unit for minimizing the building operational cost without sacrificing temperature requirements. First, the system was briefly introduced and the dynamic thermal process models of building structure and LHTES unit were developed. Then, a hierarchical control structure with dynamic multi-swarm particle swarm optimization was presented to address the dimensional challenge and discontinuities in control variables. Due to the considerable decrease of optimization variable space, the method presented in this paper enables long-term simulation and application in a real controller. Simulations were carried out based on a typical TBS building located in Beijing, China. The total energy consumption of the cooling system and the control quality of indoor air temperature were used as the criteria to evaluate the performance. Compared to a defined baseline case, the optimal control method can achieve significant energy saving, i.e. up to 18%. The impacts of the size of LHTES unit and the type of building structure were discussed, as well. The active and passive heat capacity both played a catalytic role in performance of MPC. Additionally, an uncertainty analysis demonstrated that the proposed approach has strong robustness and can handle quite high errors in forecasting building disturbances from energy consumption level. In summary, the knowledge and use of the plant system and future disturbances make MPC a powerful control tool for TBS buildings for maximizing the use of renewable energy sources.