Combined cooling, heating, power, and ventilation (CCHP/V) systems integration

Combined heat and power (CHP) systems are frequently used to reduce energy consumption in a facility due to the increased energy efficiency. System efficiencies range between 65% and 85%, whereas the average utility efficiency for electric power supply is 31% and for heating from a natural gas supply is around 80%, which yields a combined efficiency of approximately 50% for all energy supplied in the United States of America. Buildings use 70% of all electricity generated in the U.S., 40% of all U.S. primary energy to heat, light, ventilate and cool facilities. Therefore, it makes sense to site power plants near both the electrical and thermal loads to make use of the nearly 70% of energy that is annually wasted by large central power plants.;CHP systems are frequently reserved for larger facilities due to high first costs and complex operations, however 75% of all buildings in the U.S. have an area of less than 10,000 ft2 (929 m2). There have been several attempts made by various corporations to break into the micro CHP market with limited success. Studies commissioned by the Department of Energy show that two of the key barriers to the adoption of CHP systems in smaller facilities is the high first cost and the lack of packaged plug-and-play systems.;To address this challenge, the Center for Building Performance and Diagnostics (CBPD) has designed, installed, operated and evaluated a 25 kWe biodiesel fueled CHP system that is integrated with an absorption chiller system and an enthalpy recovery ventilation system with solid desiccant dehumidification in a single system that provides all of the electric, cooling, heating, and ventilation needs of the Intelligent Workplace, IW. The chiller and ventilation systems are well understood with three published dissertations in the last four years.;This dissertation integrates elements of each subsystem through the use of calibrated simulations to determine the effectiveness of operating such a system in a commercial office building as well as potentially in a data center.;Key contributions of this work include: (1) A complete accounting of how the CHP system is setup and how it operates with both Diesel and biodiesel fuel. (2) A generic preliminary design procedure for the CHP system of a building as well as the specific design procedures for the biodiesel fueled CHP system. (3) A simplified TRNSYS CHP system performance model that can be easily adjusted to be used for different buildings and/or for different prime movers. (4) A conceptual systems integration model, which identifies how components and sub-systems may fit together.;Key results in this dissertation include: (1) The results show that for efficient and effective performance of a CHP system in a high performance building it is essential to have electrical and thermal grids available to export and/or import CHP energy. The grids allow the CHP system to operate continuously at the design load. The grids also provide back up in case of system outage. (2) The results of operating the biodiesel fueled CHP system in the 1W yields an average annual efficiency of about 66% and a peak of 78%. (3) A scaled up system for the Building As Power Plant (BAPP) will achieve similar efficiencies unless a larger load for the coolant energy can be found. (4) Data centers offer an ideal location for CHP systems as they do not have such highly variable loads such as office buildings. Furthermore, data centers do not have latent cooling or heating loads, which simplifies systems integration, as the only components required for the system are an engine or turbine, heat recovery equipment, and absorption chillers. A CHP system with absorption chillers has been calculated in this dissertation to achieve an average efficiency of 78% in data centers.;There are many possible next steps; however the three most important steps in the development of the CCHPN technology are to complete the automation and integration of the CHP system with the rest of the IW.;Second, to refine the BAPP data for the TRNSYS simulation and to create a modular CHP system in TRNSYS so the development of BAPP mechanical system can proceed and provide a future testing ground for packaged CCHPN systems.;Third, to conceive and develop the means for reducing equipment and installation costs by a factor of 10 to 20 must be developed.