Pre-cooling Systems Research Articles

Energy Saving and Payback Period for Retrofitting Air Conditioning Systems in Taiwan

In Taiwan, AC systems in buildings with central air conditioning account for over 45% of the total electricity consumed. Inefficient and poorly designed AC systems in existing buildings waste considerable amounts of money and energy. Therefore, retrofitting AC systems has become a widely adopted strategy to save energy while maintaining a comfortable indoor thermal environment. This study analyzes the potential energy savings and payback period of retrofitting AC systems in public buildings. In addition to the required Building Energy Management System (BEMS), several measures are introduced to reduce energy consumption during retrofitting. The main measures include testing, adjusting, and balancing (TAB) of existing AC systems; replacing over-designed chillers with chillers with smaller capacity; installing frequency conversion in original systems, such that they become variable water volume (VWV) and variable air volume (VAV) systems; and utilizing CO2 concentration control and pre-cooling air systems. Based on analytical results, we conclude that AC system retrofitting can reduce total energy usage by 11.75%, while the average payback period for a retrofit project is 4.71 years, demonstrating that AC system retrofitting in Taiwan is economically sound.

Up-to-date Status and some Problems of the Pre-cooling Systems for Vegetables

Up-to-date Status and some Problems of the Pre-cooling Systems for Vegetables

Pre-cooling systems for small-scale producers

Purpose of review: To identify pre-cooling systems and cooling methods that are suitable for smaller scale horticultural producers Findings: A range of pre-cooling systems are available for small-scale horticultural producers and their suitability is described, in terms of availability, ease of use, capital cost, energy requirements. Expected benefits of using pre-cooling are also discussed. Limitations: Many of the mobile pre-cooling systems currently available on the market have been developed by commercial companies and most have not been scientifically evaluated in comparison to known stationary systems such as a cold wall. There is relatively little published information about the suitability of small-scale hydro-cooling, evaporative cooling and mobile forced-air cooling systems, especially regarding the range of crops and environments found in developing countries. Directions for further research: Future research needs include identification and characterization of lower cost pre-cooling methods and continued efforts to improve their cooling efficiency and reduce their energy use. Efforts to standardize and test management practices that conserve energy should be undertaken in order to further improve financial benefits.

Development of Preloading and Precooling Systems for a Single-Turn Ignition Tokamak

A basic requisite of the Fusion Ignition Experiment (IGNITEX)1 is the production of a high (20 T) toroidal field (TF) by a single turn coil. The proposed high-field technology uses precooling and preloading systems. The Ignition Technology Demonstration (ITD) program, designed to produce 20 T on axis in a 0.06 scale prototype TF coil, utilizes a preloading structure and a precooling system. The preloading structure is a hydraulic press built around the TF coil, capable of a force of 1.1 Mlb (4.9 MN) and a stroke of 0.5 in. (1.3 cm). The precooling system is an open-top LN2 cryostat tub integrated into the preload press. The IGNITEX experiment is estimated to use a preload press with force capacity of approximately 150,000 tons (1.3 GN), and with a stroke on the order of 2 in. (5.1 cm). Design considerations include efficient use of material, design of large scale hydraulic actuators, shielding to reduce radiation from activated material, maintenance, cost, and reliability. The precooling system design involves considerations of feedthroughs, minimal cooling time between pulses, maintenance and reliability.

Management Practice of the Pre-cooling Systems for Vegetables

Management Practice of the Pre-cooling Systems for Vegetables