As a change of culture in the use and rationalization of the air conditioning system, the coal company based in Colombia, Cerrejón, obtained about 50% energy savings.
by: Carlos Padilla Posada*
The decrease in energy consumption and the implementation of increasingly efficient air conditioning systems are framed in the responsible mining policy that constitutes the hallmark of the Cerrejón coal complex, in the Colombian Guajira. In an area of Colombia with an almost desert climate, where temperatures above 34°C are recorded, the air conditioning service is a priority and additionally becomes a critical point in terms of energy savings. Under this premise, for the commercial area of the camp of the mining complex, an ice water system was implemented that allows to provide the air conditioning service simultaneously to the Makuira Auditorium, the Calaguala Hall, the Bowling Alley, the Church, the Art Cinema and twelve (12) commercial premises near these buildings.
The implementation of a conventional ice water system meant by itself an improvement in consumption from 1.3 Kw per ton consumed by pre-project equipment (equipment of more than 15 years of use) to 1 Kw per ton. However, the real success of the project turned out to be the implementation of a single water chiller unit of just 140 tons of cooling to serve all these sites, which in total consume 240 tons of cooling. How was it possible? The answer to that question is summed up in a change of culture.
The work team, led by the Superintendence of Engineering and Projects of Cerrejón and where the companies Alejandro Faccini & Cía. Ltda. as Consultant, and Servipáramo S. A. also participated. as an installer, he established that the different areas to be conditioned were close to each other and brought together the inhabitants of the mining camp at different times and in different numbers, which facilitated the implementation of an ice water interconnection system without major challenges in the installation. With this starting point, it was defined that the use of the enclosures and the air conditioning service should be regularized, to allow a high diversity factor.
Established the parameters of the system, which included the calculation of the fixed load of the project represented in the commercial premises, as well as the calculation of the highest possible demand of the project, which turned out to be the Makuira Auditorium for being the installation of the largest built area and with the greatest capacity to accommodate people, the task of having just over half the capacity of condensing units for a capacity of handlers was achieved. Established.
Shift to energy efficiency culture
Once the system was installed and put to the test with an event that managed to bring together the vast majority of the inhabitants of the residential unit of the mining complex, the next step was to make the necessary adjustments to rationalize the service and promote a change in the culture of the inhabitants that aligned them with energy efficiency.
With the support of those responsible for the management of the residential unit, defined schedules have been reflected in the ice water system according to the use of each enclosure and the need of each group of the community. The schedules outside this program are coordinated directly with the Superintendence of Engineering and Projects of Cerrejón to handle possible load deficiencies due to simultaneous occupations of the conditioned facilities.
The conjunctures of simultaneous occupation of the facilities have not been a problem for the operation of the system and have been handled with a pre-cooling of the areas an adjustment in the final temperature of the enclosure at the upper limit of thermal comfort. So far, after a year and a half of operation of the system, there have been no canceled events or with thermal deficiencies. The inhabitants and users of the residential unit, aware of the active contribution that we must all have in the rationalization of energy and in general of all our resources, have accepted technological change very willingly, learning to request in advance the programming of air conditioning equipment and ensuring that they are not used unnecessarily.
Efficient air conditioning, synonymous with responsible mining
The ice water system installed in the commercial area of the residential unit of the Cerrejón coal complex, with which a wide reduction of installed tons was achieved, is not only a successful project from the point of view of energy efficiency. It also provides a direct aid to the environment by using eco-friendly refrigerant and replacing more than 480 pounds of R22 refrigerant, identified as an ozone layer attacker, decreasing the amount of hot air expelled into the atmosphere that directly or indirectly contributes to global warming.
The project developed is part of an ambitious program to change air conditioning equipment that is being implemented in Cerrejón and is aligned with the corporate policy of responsible mining. In the residential unit of the mining complex alone, more than 600 tons of refrigeration have been replaced in equipment that used R22 refrigerant and generated consumption of around 1.3 Kw per ton, by equipment of ecological refrigerants and SEER 13 efficiencies.
The change of equipment in the houses has been very well received by the inhabitants of the residential unit, who have understood the inconvenience associated with the dismantling and installation of new equipment and have assimilated their role as main contributors in the rationalization of energy. The change of equipment that has been executed throughout the mining complex during the last three years, framed in migration schemes to equipment of greater energy efficiency and use of ecological refrigerants, corresponds to the planting of around 7000 virtual trees. Each ton of refrigeration replaced corresponds to the planting of at least 10 virtual trees that favor the reduction of CO2 levels in the environment. In a complex with more than 6,000 tons of refrigeration installed and expanding, a great potential for ecological management is clearly configured.
In the future, Cerrejón plans to continue cultivating in the residents and users of its facilities the culture of rationalization of the air conditioning service, essential to maintain even lower consumption levels than those obtained directly through the installation of equipment of greater energy efficiency, and advance in the implementation of automated systems that allow centralized control and minimize the unnecessary use of the service.
* Engineer Padilla is the controller of air conditioning projects at the Colombian company AB Proyectos S. A. He can be contacted at the PBX. 57-5 3502007.
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