Content
 Introduction
 RTS Concept / Theory
 Demonstration
Introduction
 What is ECOHEAT?
 A software which could be used to calculate/estimate
the Cooling & Heating Load needed for a particular
space.
 Main usage is to assist the designer in sizing the indoor
units.
 Developed based on the most recent ASHRAE
handbook.
Available Methods
 Transfer Function Method
 Involves many calculation steps.
 More oriented to average hourly cooling load than peak design load.
 Total Equivalent Temperature Differential (TETD) method
 Needs a lot of user judgment (e.g. time averaging period) primary
usefulness has always been to the experienced engineer.
 Cooling Load Temperature Differential (CLTD) method
 Single step technique that proceeded directly from raw data to
cooling load without intermediate conversion of radiant heat gain
to cooling load.
 Factors such as CLTD, cooling load factor (CLF) are limited to
specific building types and conditions-> invalid beyond the range of
applicability.
Available Methods
 1996 –ASHRAE Load Calculations Technical Committee funds RP-875; goal
is to replace existing methods with:
 Heat Balance Method (most fundamental method)
 Radiant Time Series Method (simplified method, intended to be
derived directly from HBM, but be much easier to use; a “spreadsheet
method”)
 2001 –HBM and Radiant Time Series (RTS) Method are published in
ASHRAE Handbook of Fundamentals.
 The primary benefit of HB and RTS calculations is their somewhat
reduced dependency on purely subjective input in conventional methods:
 determining a proper time-averaging period for TETD/TA;
 Ascertaining appropriate safety factors to add to the rounded-off TFM
results;
 determining whether CLTD/CLF factors are applicable to a specific
unique application.
RTS Concept / Theory
 What Radiant Time Series does??
 Used to convert the radiant portion of heat gain to
cooling load. (by a series of coefficients dependent on
building type)
Radiant Time Series Method
Internal Heat Gain
 Residential Calculation: utilises correlation to get
the total heating/cooling load.
 Function of number of people, floor area.
Internal Heat Gain
 Non-Residential Calculation: treat the internal heat
gain individually More EXACT !!!
 Consists of peoples, lighting, PCs, monitors.
 It is general, can be used for residential applications as
well.
Surface Elements
 Wall/Door/Window Exterior : Wall/Door/Window
exposed to direct sunlight.
 Wall/Door/Window Interior : Wall/Door/Window
NOT exposed to direct sunlight.
 Floor:
 On-Grade: Attached to earth (adiabatic for cooling
load, no infiltration)
 Below Grade: Attached to underground (adiabatic for
cooling load, no infiltration)
 Above Grade: Floor above earth level (infiltration
happens, heat transfer occurs)
Building Types
Demonstration
Floor plan of a typical bedroom
Thank You…