A First-Order Study of Reduced Energy Consumption via Increased Thermal Capacitance with Thermal Storage Management in a Micro-Building

Abstract

This study uses a first-order approximation of a micro-building to investigate the major factors determining how increased thermal capacitance (ITC) with thermal storage management (TSM) can reduce energy consumption in locations with relatively mild weather conditions such as the southeastern part of the United States of America. In this study, ITC is achieved through water circulation between a large storage tank and pipes embedded within the building envelope. Although ITC results in a larger dominant time constant for the thermal response of a building, an adaptive allocation and control of the added capacitance through TSM significantly improves the benefits of the extra capacitance. This paper compares two first-order models for a micro-building: a reference case model with a single lumped thermal capacitance associated with the building, and another model, with the building's capacitance plus the capacitance of the water system. Results showed that the ITC/TSM system reduced the cost of conditioning the building by reducing the operating time of both the cooling and the heating systems. May through September, the air conditioning operating time was reduced by an average of 70%, and October through April, the operation of the heating system was reduced by an average of 25%.

Building Energy Management Using Increased Thermal Capacitance and Thermal Storage Management

“…The requirements for these valves are listed in Table 5. A large water tank was used to significantly increase the time constant of the building [19]. To retain a large thermal time constant and reduce the size of the tank, a phase change material (PCM) was added.…”

“…If these methods used permanent installations, such as buildings constructed with a high thermal mass, then benefits could have been lost when a low thermal capacitance is favorable. Due to this, investigations into active thermal mass and thermal storage methods are of interest [14][15][16][17][18][19]. Carpenter et al [16] found building energy consumption reduced when implementing increased thermal capacitance though water circulation in the shell of the building.…”

Harnessing the Flexibility of Thermostatic Loads in Microgrids with Solar Power Generation

“…This approach has been previously used in [14,20,55,59], among other works, to capture first-order transients without having to perform a heavily-detailed building simulation that would require an extensive previous knowledge of the buildings and their processes. Another advantage of having a relatively simple building model is that it also facilitates the real-time implementation in control systems, such as the optimization framework we propose in this work.…”

“…While [26,55,58] acknowledge the importance of variable COP, limitations with the black-box simulation software they employed precluded them from modeling a variable COP. We adapted the work of [56,62], where COP for heating and cooling were modeled as a quadratic function for a fixed supply temperature based on regressions from catalog data.…”

“…Reduced-order building models have been extensively proposed in the literature for satisfying different objectives; e.g., to test the effect of new building components [55], to size building components [56], to optimize building operation schedules and controls [26,27,[56][57][58] or forecast the energy performance of buildings [27].…”