ECOHEAT: Cooling & Heating Load Calculator Software Yap BT email:yapbt@oyl.my

1. ECOHEAT: Cooling & Heating Load Calculator Software Yap BT email:yapbt@oyl.com.my

2. Content • Introduction • RTS Concept / Theory • Demonstration

3. 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.

4. 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.

5. 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.

6. 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)

7. Radiant Time Series Method

8. Internal Heat Gain • Residential Calculation: utilises correlation to get the total heating/cooling load. • Function of number of people, floor area.

9. 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.

10. 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)

11. Building Types

12. Demonstration Floor plan of a typical bedroom

13. Thank You…