Power consumption no longer a concern when planning the design of a building subject. There are strategies that can reduce these consumption and also make a valuable contribution to confrot and the environment.
by José Luis Correa *
The energy performance of a building is a critical element in the design of sustainable buildings. There are many energy conservation strategies to optimize such performance, then, knowing to choose which of these provide greater benefits, it is a fundamental step in the design process of a project. Building energy simulation meets these needs, however, its usefulness and application requires a thorough knowledge of its characteristics.
The energy efficiency of a building depends on its design. Its shape, orientation, materials and construction methods, envelope, water management, as well as heating, ventilation and air conditioning (HVAC) and lighting systems, determine the level of efficiency with which the building uses energy. Therefore, the most effective way to optimize energy consumption is using a comprehensive approach in which the building look like a total and interconnected whole.
In addition, the collaboration of all members of the design team from the beginning of the project, is also essential. Thus, a holistic view of each of the participants of design meetings will be crucial in achieving the objectives of sustainability and energy efficiency set by the customer.
The certification system for sustainable buildings LEED (acronym for Leadership in Energy & Environmental Design), recognizes the importance of energy consumption through mainly two issues. The first issue is related to the 2 prerequisite chapter Energy and Atmosphere 'Minimum Energy Performance', which claims that the building designed, and its systems have a minimum level of efficiency, to reduce the economic and environmental impact associated with excessive use of energy. The second issue relates to credit 1, the same chapter, called 'Performance Optimal Energy', which seeks to achieve a level exceeding the requirements of the prerequisite 2 energy efficiency; what rewards, giving the most points that a project can get in a single credit.
These two issues require for compliance of the total simulation designed building and demonstrate energy savings this respect to a baseline established in a reference standard. Thus, LEED invites sustainable buildings to achieve higher levels of energy efficiency through the integration of simulation tools to design processes.
90.1 ASHRAE is the technical standard referenced by LEED, which provides the necessary guidelines to meet the energy performance required by this certification. This is an industry standard that provides not only the minimum requirements for the energy efficient design of commercial buildings, but also establishes criteria for determining compliance with such requirements.
Projects seeking LEED certification and keep the option of full simulation of the building, can demonstrate improvements in energy efficiency of your project using the 'method of evaluating the performance of buildings' detailed in Appendix G of the standard question. Suggesting that the ASHRAE standard 90.1 and energy simulation, are strategic when designing buildings that expected savings in energy consumption deserving of the LEED certification allies.
A very useful evaluation
Simulation is an art as a science. The simulation of the energy performance of a building is a powerful computational tool that architects, engineers and builders, among others, should be used to assess how each system of a building affects the total energy consumption of the same.
The result of such assessment is useful when inform and guide design decisions impact on energy consumption. Although many designers are qualitatively aware of the high level of interaction between different systems of a building, it is difficult - and in some cases impossible - to quantify such interactions accurately, unless the building simulation is done. All this suggests that the simulation strengthens and facilitates the work of designers, answering key questions when characterizing their projects.
According to the phase in which the project is, energy simulation can answer questions such general or specific design as required. Some of the most common concerns of designers, and can be evaluated with the simulation are as follows:
- What level of thermal insulation is more profitable for walls and ceiling in a particular location?
- Is it profitable in temperate climates, window frames with double panel?
- If you install efficient lighting system, how much the size of the cooling system will decrease?
- What would be the impact on energy consumption by adding more windows to a building?
- How much energy would be saved if a specific component is used to increase the energy efficiency of an air conditioning system?
There is a wide range of topics that energy simulation of buildings can be assessed, however, it may not be appropriate for some projects.
Although energy simulation can add significant value to the process of building design, this is not always the case. There is no quick and simple method to determine when a simulation or not, but if there is a set of typical signs that suggest refrain from performing, as described below:
- When the design process is so advanced that it is unlikely that anything can be changed.
- When a project is so small that the cost of doing a simulation is not profitable.
- When questions of design, which are required to respond, are outside the scope of program evaluation simulation or knowledge of the simulator.
It is the responsibility of the consultants energy efficiency clearly explain to the customer the constraints of their simulation programs, so as not to generate false expectations.
Energy simulation widely contributes to the optimization of energy consumption of buildings. Its integration into the design process is essential in planning projects with high performance and / or aspire to LEED certification. And although its application is not beneficial in all cases, in the vast majority of projects can guide designers towards the implementation and optimization of key energy conservation strategies. thus contributing to a better society through the optimization of sustainable buildings, ie profitable, comfortable and low impact on the environment constructions.
* José Luis Correa Guzman is Engineer, MSc, LEED AP O + M, next president of ASHRAE-Colombia. Senior Consultant Sustainable Construction: Energy & Comfort and director of the company KW Engineering. He can be reached via e-mail: firstname.lastname@example.org or visit the website: www.kwingenieria.com.