Lecture Objectives: Answer question related to HW 4 Learn about Life Cycle Cost Analysis (LLC) tools in eQUEST Learn about specifics related to modeling of HVAC systems

HW 4 Modeling based on Measured Data Location: Syracuse

HW4 Empirical model: Q=f(DBT)

What are the reasons for the energy simulation? Design improvement Economic benefits Budget planning

Life Cycle Cost Analysis Engineering economics

Life Cycle Cost Analysis Engineering economics Compound-amount factor (f/p) Present worth factor value (p/f) Future worth of a uniform series of amount (f/a) Present worth of a uniform series of amount (p/a) Gradient present worth factor (GPWF)

Parameters in life cycle cost analysis Beside energy benefits expressed in $, you should consider: First cost Maintenance Operation life Change of the energy cost Interest (inflation) Taxes, Discounts, Rebates, other Government measures

Example Using eQUEST analyze the benefits (energy saving and pay back period) of installing - low-e double glazed window - variable frequency drive in the school building in NYC

Building and its HVAC Systems (Primary and secondary HVAC system) air surroundings Zone (Loads) mix box supply fan cooling coilheating coil chillerboiler cooling tower pump Secondary System Primary System

Integration of HVAC and building physics models Building Heating/Cooling System Plant Building Heating/Cooling System Plant Load System Plant model Integrated models Q buiolding Q including Ventilation and Dehumidification Secondary systemsPrimary systems Enable component-based modeling

Solving linear and nonlinear System of equations HVAC Two separate systems: - Building physics (zone): set of linear equations - HVAC nonlinear equations We used separate solvers and then iterate

Iteration type Time step Time step Building physics HVAC Building physics HVAC

Solving linear and nonlinear System of equations

Component-based simulation programs - Trnsys

Component-based simulation programs - Energy Plus