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1981 IIAR Technical Paper
3rd Annual Meeting
Use of C02 in Controlling Ammonia Leaks
Author: Eric Pugh
Frigo Quebec, a cold storage warehouse divided into eight major areas and containing five different lessees, had experienced a major ammonia leak, to the extent that it was impossible to enter the largest of these areas without an external oxygen supply. First attempts to dampen the odours and reduce contamination involved the use of dry ice. Sufficient quantity was difficult to acquire quickly and the amount of time and labour involved was prohibitive, but the exercised did result in some effect on the ammonia levels within the room. In all, 21,500 lbs. of liquid C02 and 8,200 lbs. of dry ice were used over 4 days. Odour control could not be exercised by one massive dose: continuing operations stirred up more and more ammonia, so continuous monitoring was required.
Computer Controls for Ammonia Refrigeration Systems
Author: Richard Oas
My talk will briefly describe the programmable controller installations, the computer installation at the Distribution Center in Chester, Virginia and their cost-effectiveness. The main focus of the talk will be the computer installation at the Milk Plant in San Leandro, California. Factors concerning cost, capabilities, reliability, maintenance and pay back will be presented. In closing, I will also mention the Computer Aided Drafting System at Safeway's headquarters. This system is used for preparing warehouse assignment drawings and refrigeration bid and construction drawings.
Author: Stan Tory
Energy conservation is an extremely diverse and established concept. It has certainly been around since man's presence in one form or another and is probably one of the first engineering principles developed. The intent of this presentation is to address energy trends as they have affected Pacific Gas and Electric Company and its customers in Northern California, and to help equipment suppliers and manufacturers understand the need to assist regulating organizations, government at all levels, and utilities in making energy related decisions. Since the presentation utilizes a number of slides, a narrative summary and two more detailed articles describing PGandE's commercial-industrial and agricultural conservation efforts follows.
The Impact of Solid State Electronics on Control of Industrial Refrigeration Systems
Author: B.B. Chidester, F. M. Laucks and A. J. Marshall
The discussion at hand today -- The Impact of Electronics on Refrigeration System Control -- is really an evaluation of one effort to overcome the dual problems of shortage and high cost of qualified technical personnel to run our refrigeration plants. We will first deal with the problem of controlling large installations with many pieces of similar types of equipment and then will discuss in detail what can be done with a single screw compressor in terms of data monitoring, evaluation and retrieval.
Ammonia Refrigeration in the Wine Industry in California
Author: Gary C. Dunn
This paper describes: Users and non-users of ammonia systems, what gets cooled at what stage of production, types of evaporators used in each stage of production, and the most frequently used and crucial "rules-of-thumb" for designing winery systems.
The Control of Evaporative Condensers and Freezing Coils And How It Effects Cost of Operations Based on Ammonia Refrigerant
The United States has approximately 5% of the world's population and uses 31% of all the world's electrical energy produced. One of the major reasons for such waste is most all decisions are made on initial cost and not operating cost. It should be the goal of all to change this approach. By use of an E.M.C.S. (Energy Management Control System), to monitor all parameters that effect operation of the refrigerant system and taking corrective action when necessary, we will conservatively save $88,000.00 in power per year based on .05 cents per kw at 1,000 tons mean load. These savings at .07 cents per kw under the same conditions would be $123,000.00 power savings per year. We need to do this for the good of all. Everybody wins with sound business and engineering practices.
Efficient Thermopump Cooling of Reciprocating Ammonia Compressors
Author: Vagn Villadsen and Fleming V. Boldvig
This paper presents a new, patented cooling system for reciprocating compressors operating with R 717 (Ammonia), developed as an alternative to conventional water cooling. The thermopump will cool compressor oil and discharge gas by direct expansion. The system is described in details and the efficiency is illustrated by a series of comparative tests run with a SABROE reciprocating compressor type SMC 6-100, having 6 cylinders of 100 mm bore x 80 m stroke and a speed of 1480 rpm. The tests compare the cooling effect of the followinq systems: a - air cooled top and side covers b - water cooled top cover and oil cooler c - thermopump cooling. The thermopump cooling system has a number of advantages, viz. lower compression temperature and discharge gas temperature - no corrosion problems - no freezing risk - factory mounted - no water piping installation on site.
Programmable Controllers for Industrial Refrigeration Plants
Author: W. F. Stoecker
The availability of microcomputers for control purposes has opened new approached to monitoring and controlling mechanical and thermal equipment. The industrial refrigeration industry also feels the impact of this new technology. There are many different approaches to what is controlled and how the control is achieved in industrial refrigeration facilities and it is sometime difficult to find the common thread that facilitates understanding the hardware and the concepts. One of the approaches to assessing the new developments in computer control of industrial refrigeration systems is to investigate programmable controllers, (PC's). The reason that this approach might be fruitful is that most of the computer control systems available on the market today have grown out of the PC technology. In fact, some of the computer controllers being applied to industrial refrigeration plants today are what might be considered enhanced PC's. This presentation, then, will consist of two major sections: (1) explanation of the function and use of PC's, and (2) an introduction to microcomputer control, since virtually all PC's are microprocessor based.