Auditoria Energética Preliminar

AUDITORIA ENERGÉTICA PRELIMINAR

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ASHRAE categorizes Energy Audits in three different levels of energy analyses according to the effort required, and it recommends starting with a Preliminary Energy-Use Analysis.

• Preliminary Energy-Use Analysis (PEA) precedes an energy audit, and is of great use in cases where the level of effort of the audit has not yet been defined. During the PEA, the historic utility use, peak demands, and costs are analyzed; in addition, the Energy Cost Index (ECI) and Energy Utilization Index (EUI) are developed.

• Preliminary Energy Audit (Level I), also known as a ‘Walk-Through Survey’, is where the building´s energy cost and efficiency are assessed analyzing its historic energy bills, and a brief on site survey is conducted. The survey identifies low-cost and no-cost measures to improve energy efficiency. Level I audits are useful when the desire is to establish general energy savings potential or to establish which building within a portfolio has the greatest savings potential.

• Detailed Energy Analysis (Level II) involves a more detailed building survey, including an energy consumption and peak demand analysis. A breakdown of the energy use within the building is developed, and the savings and cost analyses of the energy saving measures (ESMs) are provided.

• Detailed Analysis of Capital-Intensive Modifications (Level III) or viability studies (investment grade). This level requires more field data gathering and rigorous engineering and economic analyses of the projects identified in Level II. The results provided in this level are detailed project cost and savings calculations with a high level of confidence, sufficient for major capital investment decisions.

As Good Practice, it is recommended to divide the Energy Audit into three stages:

1. To ensure financial sustainability of your client
2. Obtain the Energy Baseline
3. Analyze the Energy Saving Measures that will require financing and suggest the Implementation Plan referred to the financing resources gotten.

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What and in which order should the ECMs be evaluated

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Example of an audit scope

Make sure that the Scope and Extent of the Energy Audit is well defined prior to the start of it. This is extremely important in order to avoid any future misunderstandings.

Obtenha:

• Contas de eletricidade
• Contas de combustível
• Dados de produção (hotel = taxas de ocupação)
• Dados climáticos
• Especificações e desenhos das instalações
• Benchmarks do setor
• O que mais julgar necessário

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O processo de auditoria energética

EUI: Energy Use Index,

ECI: Energy Cost Index,

LCA: Life Cycle Analysis

O que registrar na auditoria energética

Visão geral

1. Dados da organização
2. Distribuição do consumo e do custo da energia durante, pelo menos, um ano
3. O benchmark de EUI e ECI da instalação
4. Medidas propostas, com as respectivas estimativas de economia de custos com energia e payback de cada investimento
5. Processos operacionais na instalação, consumo de energia, planos de melhoria, finanças, sazonalidades, fornecedores principais, etc.
6. Análise detalhada das contas de energia (Sankey Diagram, sankeymatic.com/build/).
7. Sistemas de energia instalados e em operação. If estimated, the main assumptions must be clearly mentioned
8. Sistemas de controle e lógica dos principais sistemas
9. Medições de cargas
10.  Imagens térmicas

Medidas de economia de energia (ESM)

1. Seção de brainstorm com o cliente
2. Análise qualitativa das ESMs: prioridade e complexidade
3. Descrição das esm
4. Seleção das ESM

Avaliação financeira

Plano de implementação, etc.

Referência

Ruz, A. M.; Hinojosa, L. Energy Audits: Good Practice Guide. International Development Bank. 2013

Leitura complementar (para elaborar o modelo a ser usado na auditoria energética)

ASHRAE. Procedures for Commercial Building Energy Audits. Atlanta, GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. 2011. (see the attached worksheets)

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