We continue with the second of three parts of this interesting article that talks about how to design, install, operate and maintain high performance air conditioning systems.
by Camilo Botero *
In the previous edition mentioned topics related to high performance air conditioning, the phases of a project, quality assurance, and the issue of energy efficiency under the concept of BEQ (Building Energy Quiotient), now we will continue to break down this last concept and other phases of planning an excellent HVAC design.
There is an energy efficiency label that informs about the use of potential and real energy in a building and also provides feedback to the owners and operators of how their building is behaving. It informs owners and buyers of the efficiency with which a particular building performs and projects the long-term costs of energy use.
The bEQ, is a great differentiator that gives great prominence to buildings with zero or positive energy balance, and highlights high-performance buildings; the ones that are in the average are determined and finally the inefficient or unacceptable ones are specified, which can be penalized or their operation impeded. It focuses only on documenting and understanding energy, identifying opportunities to improve its performance, during the operation and also allows making comparisons between different buildings that have the same use.
On another subject, a strategy of high energy efficiency constitute the Thermal District Cooling, which are centralized large systems that produce cold water, which is carried by pipeline networks properly insulated, the lead through an area default, supplying the energy needed to heat several buildings at once, with considerable benefits since the simultaneity factor is considerably reduced, thus being able to have centralized systems much smaller, relative to the thermal load installed in buildings, increasing considerably the efficiency of systems and minimizing the installed capacities.
Optimization of air conditioning
For the optimization of air conditioning, all the innovations that have been incorporated into this industry are used, one of them is the rational use of energy, through control, to achieve that the most precise amount of energy required is consumed. to partial loads by demand of air conditioning.
There are excellent protocols, programs, sensors, valves, actuators, etc., that allow achieving that coupling between the demand profile of the systems and their energy consumption without deteriorating compliance with the design parameters. I think we could make more effort in this issue of systems control, encouraging the training of engineers and technicians who know the fundamentals and applications of controls, but who understand how thermal systems are, since they react in minutes, hours and even days, while the control systems react in fractions of a second. Lack of knowledge of this principle, very often results in control systems that do not operate properly.
This implies substantial changes in technology such as designing with all available technological resources and I will mention only some: "Free Cooling" of all kinds, Heat Pipe, CDQ, Convert, Superheater in the Cooling cycle, Cold Beams, Controlled Solar Light Lighting, Supply by Below (UFAD) and Ventilation by Displacement, Cooling with Piping in Walls, Floors and Ceilings; Entálpicas Wheels, Heat Exchangers of All Types, Peltier Effect, Cogeneration and Trigeneration with Residual Heat, Direct and indirect Evaporative Cooling, etc.
The foregoing must be accompanied by bold proposals in legislation - standardization, in addition to very effective methodologies during the phases of predesign, design, construction, operation and maintenance of buildings such as commissioning (assurance of quality throughout the life of the project) and energy audits; but above all a deep awareness of the need and kindness to incorporate this concept, our daily life.
In parallel, it has been promoting and upgrading the use of standards, codes and regulations in Latin America and specifically in Colombia, as the resolution 0549, which already requires from 2017, very significant reductions in energy consumption, leading to systems high efficiency, environmental protection, compliance with design parameters, especially on issues such as air quality inside. ASHRAE in this respect does a wonderful job writing guidelines, standards and even a language code which will then be binding. We must learn from this association.
In Colombia the RITE 2017 version was developed (Regulation of Thermal Installations in Buildings), which contemplates, our climatic and constructive conditions, as well as the systems of commonly used units, the own terminology; This RITE 2017, has already been incorporated as the BPI 09 of ACAIRE (Good Engineering Practice), which is used more and more, but which does not have the required impact, since it is not yet a mandatory regulation. The day that is finally approved by the state and becomes mandatory compliance will significantly improve our air conditioning projects, with a great impact on the increase of energy efficiency.
The consultants and designers must be engineering professionals with deep knowledge of psychrometry, heat transfer, fluid mechanics, turbomachinery, selection of existing multiple systems, in-depth knowledge of the technologies available at the design date that point to the maximum efficiency and the rational use of energy, with control strategies that adapt very precisely to partial loads.
Once the project requirements specified by the owner have been drawn up, the design bases, a Quality Assurance plan, the following Construction and O & M processes must be continued.
* Camilo Botero is the current Secretary of the Federation of Latin American Associations Air Conditioning & Refrigeration - FAIAR; he was president of ACAIRE and is president of Camilo Botero Ingenieros Consultores Ltda. He has taught in several Colombian, guilds and now universities in ACAIRE courses graduate air conditioning projects, energy efficiency in air conditioning and refrigeration, cogeneration and trigeneration , psychometrics applied thermodynamics, fluid mechanics, heat transfer and turbomachinery. (Cbg@cbgingenieria.com).