Finding the latest feasible HVAC start from weather and building response

01 · CASE ANALYSIS

Define the service target

The source model aims for 22°C in winter and 24°C in summer at 08:30. Winter uses outdoor temperature; summer includes temperature and humidity through outdoor-air enthalpy.

The objective is the latest feasible start, not the earliest possible start. Enough pre-operation must remain to meet the modeled occupied-start condition.

02 · CASE ANALYSIS

Reproduce the model assumptions

Initial indoor conditions are estimated from midnight weather and day type. Minute-step calculations combine thermal loss/gain with HVAC temperature response.

Source parameters include heating rate 3.5°C/h and loss rate 0.07, and cooling rate 4.8°C/h with gain coefficient 1.0. These are model inputs, not universal building constants.

03 · CASE ANALYSIS

Read the historical-weather output

For 151 winter days, mean optimal preheating was 3.90 h/day with range 0.18–8.50. For 153 summer days, mean precooling was 0.95 h/day with range 0.00–2.28.

The source does not numerically define the existing site fixed-start baseline. Consequently no start-time reduction percentage or energy-saving rate is inferred here.

04 · CASE ANALYSIS

Calibrate before operational use

Collect outdoor and indoor temperatures, HVAC states and occupied-start service over several weeks. Refit initial conditions and response rates and compare predicted against actual arrival conditions.

For M&V, record all relevant pre-start electricity, gas and heat at the same boundary and compare actual energy with a weather-adjusted fixed-start baseline.

Source figures · English edition

Figures correspond to those published in the Korean case. English titles, axes and legends are provided; published values and evidence boundaries are retained. Open a figure at full size to inspect small labels.