OTHER APPROACHES

By: Americ

by ACAIRE

We must protect future generations from the irreversible consequences of the depletion of our lands and their bio-climates, as well as from predictable climate changes, which are predictable precisely because of their dire consequences for all of us who share this earthly atmosphere.

Integration

CVAR engineers in Colombia have accepted this historic responsibility. Hence, the need to integrate and rethink engineering management with the associations that make up FAIAR (Federation of Ibero-American Associations of CVAR) and AASA (Alliance of societies affiliated to ASHRAE).

This integration should be quickly materialized in the permanent exchange of proposals and in the transfer of technology between the countries that make up the FAIAR, with ASHRAE as the axis of this process. To make that experience a reality, it is necessary to accelerate this transfer and anticipate the needs of a new sustainable world, which we will have to design and build from now on.

As a concrete beginning of this task, ACAIRE (Colombian Association of Air Conditioning and Refrigeration) is leading the development of a proposal for statutes for the FAIAR, which allow the efforts to be integrated in a coordinated manner. To this end, documents were circulated among the members for the meeting that took place in Chicago last January, in which progress was made in proposals and studies such as:

• Share the experience of AMERIC to promote, with the support of the Mexican Government, the professionalization and certification of technicians in installation and maintenance of commercial systems in air conditioning and refrigeration.

• Implementation of systems that are recognized and endorsed in our countries with common ideas, cultures and similar needs.

• Creation of a legal figure to give formality and in due course access to obtain resources to develop activities.

• Formalize a space for the exchange of experiences such as business relationships between companies and people.

• Publication of articles in the journals of the MEMBER Associations of FAIAR, or edition of a regional journal with the contribution of all members.

ASHRAE has accepted this plan to share its research and technological advances with the other FAIAR associations or the ASHRAE chapters established in the region, in a similar way in which it has been doing with other regions of the planet through AASA.

Future conversations and plans are now shown not as a possibility for years to come, but within support programs and global strategies that should be initiated in the short term.

Meeting in Chicago

In the framework of the ASHRAE Meeting in Chicago in January 2009, ACAIRE held meetings with FAIAR, AASA and also with ASHRAE on different topics: the advancement in joint programs of translation of various standards and engineering guides into Spanish; analysis of the integration of efforts in the region with FAIAR and in the world with AASA and worked on the proposal to create the Andean Chapter of ASHRAE, which will integrate the efforts of Peru, Ecuador and Colombia.

All these initiatives will mean that future generations will thank us for the commitment to provide them with a sustainable and stable future.

*Alfredo Sotolongo

In recent issues I have written comments regarding the different equipment and / or systems available to conserve energy when designing an air conditioning system.

In this edition I would like to concentrate on how you can conceive a building that complies with the so-called Green concept which means designing new buildings, remodeling existing buildings and operating those buildings in such a way that energy consumption, water expenditure, etc. is minimized. Buildings in which being environmentally responsible conditions are improved achieving a healthy environment that allows a better quality of life for the occupants.

Buildings, whether residential or commercial, greatly impact the environment. They consume approximately 30% of all energy, 60% of electricity and a large amount of drinking water only when discharging toilets. The Green concept can considerably reduce these negative environmental effects and also entails other benefits such as minimizing the cost of operation, increasing the production capacity of the people who work in them and achieving better indoor air quality.

With the purpose of uniting all those interested in achieving the Green concept, in 1993 the Council for Green Buildings of the United States, known by the acronym in English USGBC, was founded. When the members realized that buildings, mainly commercial ones, made such a marked impact on the environment, they decided to organize a system to define and measure green buildings. They developed the LEED method that translates as Leadership in Energy and Environmental Design, with which it is possible to measure how green a building is.

What it's all about

The measurement is based on points that are assigned to the building depending on what was taken into consideration at the time of design to minimize the impact on the environment. To apply for Green Building certification it is first necessary to meet a series of requirements established by the Council (USGBC) and once those requirements are met, the application process for certification begins.

The categories on which they base the score are as follows:
1. Maintenance of the Infrastructure.
2. Use of Water.
3. Energy and Atmosphere.
4.Materials.
5.Quality of the Indoor Environment.
6. Innovations in Operation and Improvements.

There are applications of equipment or materials that could help score in more than one of these categories.

Because of the length of the application process to certify a building as Green, I'm going to focus on what most directly relates to us, the air conditioning system. Although points may be obtained in more than one of the categories, Energy and Atmosphere is the one that is most directly related to our industry. Within this category are, among others, the following requirements and justifications to accumulate points:

1.How the systems are put into operation.
2.Optimization of energy consumption.
3.Education of maintenance personnel.
4.Monitoring of systems.
5.Additional protection to ozone.
6. Measurement of the efficiency of the systems and reporting of emissions.

Like everything in our industry, ASHRAE contributes several Guidelines and Standards by which the Council is guided to determine the prerequisites and how to assign points, among which are Guide 0-2005 "The Commissioning Process", Guide 1-1996 "The Process of Commissioning of Air Conditioning and Ventilation System" and Standard 100-1995 "Energy Conservation in Existing Buildings".

Many of the manufacturers of equipment and materials used in air conditioning systems have developed products that, when applied, contribute to obtaining points to certify the building where they are installed as Green. Among the examples that I can cite are:

to. In the case of the central cold water plant, Armstrong has managed, applying a control algorithm with state-of-the-art technology, to optimize the operation of all components at the same time, without having to depend on the behavior of another which makes the reaction of the system much faster to changes in thermal load.

b. In variable air volume systems, Thermafuser has managed to reduce the consumption of the fan motor of the air conditioning unit, measurement and reporting of the variables and verification of consumption.

c. In supplying outdoor air to maintain indoor air quality without increasing energy consumption, ConServ has achieved this by recovering energy from both sensitive heat and latent heat.

Awareness and budget

Today there is awareness among engineers who design air conditioning to make systems as efficient as possible, however, very few investors are aware of this need and often put obstacles to engineers when they find that to achieve it is necessary to invest a little more in their building.

However, when some time passes and they receive the bills for energy, they ask their engineers to look for alternatives to minimize operating costs and it is often too late to achieve this.

The associations of engineers should recommend to the government that laws be legislated that offer tax incentives when designing Green buildings, because ultimately it is not only beneficial for who operates the building, but also for the country because it reduces the import of oil reducing the leakage of foreign currency and in the process protects the environment.

*About the author

Engineer Alfredo Sotolongo, president of Protec, Inc., is certified as a professional engineer in Puerto Rico and the State of Florida; has more than 40 years of experience in the application and sale of systems and equipment for energy conservation. He is a member of ASME (American Society of Mechanical Engineers), AEE (Association of Energy Engineers), with whom he is certified as an Engineer in Energy Management; he is also a member of ASHRAE and was president of the Miami chapter of that association. He has also presented numerous talks on the subject of energy conservation.

Every day we encounter new challenges when we try to design an air conditioning system. These challenges are presented to us by several factors and among them the most important are: satisfying the need for the comfort of the occupants and at the same time, minimizing energy consumption.

By Alfredo Sotolongo*

In previous articles we have addressed different challenges presented by the designs in terms of energy saving, but in my opinion, one of the most delicate applications is the recovery of heat by exchanging energy between the polluted extraction air and the ventilation outside air. This is further manifested in our tropical countries where the outside air is humid and hot, accounting for up to 5 tons per 1,000 CFM that are introduced into the air conditioning system. The purpose is to process the ventilation outside air before introducing it to the air conditioning system so that when it is mixed with the return air it already has a condition where it does not penalize the capacity of the unit, avoiding increasing the thermal load.

Besides professional responsibility and the engineer's conscience, what governs the decision to specifically use air-to-air energy exchangers?

1. The existing standards published by ASHRAE and which are as follows:

to. INDOOR Air Quality ASHRAE 62 - ventilation to achieve acceptable indoor air quality.
b. Thermal comfort ASHRAE 55 – thermal conditions of the environment conditioned for the occupation of human beings.
c. Energy efficiency ASHRAE 90.1 – energy consumption in structures excluding low-rise residential buildings.

2. Other influencing factors are the following:

to. To achieve LEED™ certification
b. Contaminated building syndrome
c. To comply with the ARI 1060 standard that classifies air-to-air energy exchange equipment.

There are several air-to-air energy transfer equipment, some transferring sensitive heat only. But in this case, I prefer to refer to those that transfer both sensitive and latent heat, since with these the optimal recovery of energy is achieved. We know about enthalpy wheels and fixed plates, but before deciding which one to select we must take into consideration the following:

1.The material used to achieve energy exchange plays a predominant role in the process, as the transfer method makes the equipment more or less efficient. In addition, this material prevents contamination from the exhaust air to the ventilation air, which is of utmost importance especially in hospitals and laboratories.
2.In terms of maintenance, the ideal is that the equipment has the least amount of movable parts.
3.That their capacity is certified by a recognized institution.

This equipment is manufactured for different types of arrangements, either to operate independently using external fans, with integrated fans or inside air handling units. They offer their best service when the unit handles 100% outside air.

In the mid-70s absorbent wheels were commercially developed for industrial applications and later, in India and Sweden, enthalpy wheels, which over the years were improving energy transfer materials. However, the fact that they are porous has not allowed them to prevent the transfer of contaminants from the exhaust air to the ventilation air.

In the United States, in the mid-90s the dais Analytic company, using nano technology, developed a polymer originally for fuel cell applications. The polymer was composed of molecules of Sulfite salts (SO3) and upon confirming that it was a good heat transmitter and that its constitution allowed only water vapor molecules to pass through, from the high pressure vapor side to the low pressure side, they considered it to be the ideal material for the transfer of energy from air to air. In addition, they found that it was more efficient than the material of the enthalpy wheels and that since it was not porous, it did not allow any other type of substance to pass from the exhaust air to the supply air, including contaminants such as bacteria, etc.

The equipment for energy transfer developed by Dais Analytic is marketed under the name of ConsERV and has been a great step forward since it has no movable parts and the only maintenance that is required is to change the filters that protect both the extraction side and the ventilation side.

The engineer who designs an air conditioning system, especially where outdoor air conditions could greatly increase the thermal load, seriously thinks about energy recovery not only to meet existing standards but also his professional responsibility to offer his customer the best that is available in the industry at the time of design.

*About the author

Engineer Alfredo Sotolongo, president of Protec, Inc., is certified as a professional engineer in Puerto Rico and the State of Florida; has more than 40 years of experience in the application and sale of systems and equipment for energy conservation. He is a member of ASME (American Society of Mechanical Engineers), AEE (Association of Energy Engineers), with whom he is certified as an Engineer in Energy Management; he is also a member of ASHRAE and was president of the Miami chapter of that association. He has also presented numerous talks on the subject of energy conservation.

by Héctor Gómez Pérez

In its fifth version, Refricolombia had more than 500 participants including speakers, attendees and logistics team. We are already preparing for next year's event to be held at the Compensar Convention Center in Bogotá, Colombia, between July 16 and 17. However, it is worth retracing the steps and recapitulating some conferences that day after day become more important within the industry; on this occasion, ACR LATINOAMÉRICA spoke with Norberto Aguilar, industrial refrigeration sales engineer at Danfoss Industries S.A. de C.V., to expand the information he presented during one of his lectures at the academic exhibition and which he called CO2 refrigerant of the future.

A frequent issue on the agendas of many countries around the world is the growing importance that has been given to environmental issues. In this sense, there are many initiatives that have been launched in recent years to reduce the negative environmental impact and global warming: green buildings, cleaner diesel production, accelerated production of biofuels, energy savings in different industries and households, campaigns that promote the rational consumption of water, etc. The refrigeration industry has not been on the sidelines of this phenomenon and there is increasing talk of environmentally friendly refrigerants, including CO2.

But why did this Mexican speaker call his presentation CO2 refrigerant of the future? "A presentation by the Danish Institute of Technology indicates that CO2 is not the refrigerant of the future but the future itself. From an ecological point of view this refrigerant is a natural classification (R744), in which water, ammonia, propane, methane, etc. are also found. Among its characteristics, it stands out that it is non-toxic, non-flammable and with ODP (ozone depletion potential) classifications of 0 and GWP (atmospheric warming potential) of 1", according to Aguilar.

The first appearance of CO2 in refrigeration took place in England with a patent filed by Alexander Twining in 1850; Thaddeus S.C. Lowe experimented with it on balloons for military use, but also designed an ice machine using CO2 in 1867. Lowe in turn developed a machine to transport frozen meat on ships. This period of CO2 extended until 1930 when its use began to decrease due to the appearance of R11, R12, among others. The second moment, which could be classified as the current one, began to be generated since 1993 from the research carried out by Dr. G Lorentzen.

Compared to the group of natural refrigerants that were mentioned a few lines ago, CO2 does not have some disadvantages that they do have. For example, ammonia is toxic, hydrocarbons are flammable, and water has limited application possibilities. As for the characteristics of CO2, the one that stands out the most is its triple point that is at a temperature of -56.6 oC and a pressure of 5.18 bar. On the other hand, the critical pressure is at 73.6 bar and a temperature of 31oC.

As for the equipment, it must be considered that not all existing equipment is suitable for working with CO2, due to the pressure with which they must be put into operation. It is also important to note that the diameters of the pipes are smaller.

Other considerations and safety

In the field of industrial refrigeration, CO2 will not replace ammonia because the systems that work with it are hybrids and need ammonia or another refrigerant within a cascade system. As for its application in industry, it is used for very low temperatures (in the range of -50oC to -30oC) in refrigeration chambers or food freezing tunnels. Within domestic use it is used in heating in heat pumps and automotive air conditioning.

Unlike Ammonia, CO2 lacks a characteristic odor which is an important safety aspect. "CO2 replaces air and causes oxygen loss. In the presence of sufficient oxygen, CO2 has a narcotic effect at high concentrations, but in small amounts CO2 has a stimulating effect on breathing. Due to the acidic characteristics of CO2, some irritations may appear particularly in the mucous membrane of the nose, throat and eyes," Aguilar said.

The symptoms associated with air inhalation with CO2 are increased as follows:

* 0.04% is the concentration of CO2 in atmospheric air.
* 2% increases the rate of respiration by 50%.
* A 10-minute exposure to a 3% concentration increases the rate of breathing by 100%
* 5% represents a 300% increase in the rate of breathing. Sweating and headache appear after an hour.
* 8% is the limit of short-term exposure.
* 8 -10% there are headaches after 10 or 12 minutes, dizziness, hearing problems, blood pressure and heart rate increase, plus there is nausea.
* 10 - 18%. After a few minutes, epileptic seizures, muscle cramps and loss of consciousness may appear, in addition to shock. Affected individuals recover quickly with fresh air.
* 18 – 20%. Symptoms similar to those of a heart attack appear.
Leaks of this refrigerant are identified by infrared CO2 sensors ranging from 5000 ppm (parts per million) to 9000 ppm which is the permitted ASHRAE 15 standard.

Faced with the issue of the minimum requirements that must have the systems that work with CO2 Aguilar said that "there is a principle in refrigeration that is summarized in a good project, a good installation, zero problems. You must take into account the working pressures, the humidity that affects the system and have the corresponding safety valves."

Finally, faced with the question of the application of CO2-based refrigerants in Latin America, this was what Aguilar answered: "several applications are in projects in Brazil and Mexico; it already has the support of companies that have worldwide experience in these solutions and have a presence in Latin America. It should be noted that the first application in the region is very close. In a recent visit to a plant with CO2 application in the United States, the engineering firm told me that from 2004 to date they have 14 facilities and have signed projects until 2010. "