The history of HVAC is the history of
heating. Willis Carrier invented modern
air conditioning in 1902 to control
humidity in a printing plant, but the
industry that grew from his work was
shaped by cold-climate economics. Heating
loads drove building design in North
America and Europe for decades. Overhead
ductwork, ceiling-mounted diffusers, and
central plant architecture all assume that
the primary challenge is distributing warm
air downward in winter.
When the same infrastructure is used for
cooling, physics creates a problem. Cold
air is denser than warm air. Cooled air
from ceiling-mounted diffusers sinks and
pools at floor level. Warm air rises and
collects at ceiling height. This
temperature stratification, typically 0.5
to 1 degree Fahrenheit per foot of room
height, means the occupied zone at desk
height (0.5 to 2 metres) receives
inconsistent conditioning. Energy used to
cool air above the occupied zone is
wasted.
India does not have a heating problem.
India has a cooling problem. The Bureau of
Energy Efficiency's Energy Conservation
Building Code (ECBC 2017) addresses five
climate zones: hot-dry, warm-humid,
temperate, composite, and cold. In
cooling-dominated zones, which cover most
of the country, ambient temperatures
require mechanical cooling for the
majority of the year. The ECBC targets
energy savings of 25 to 50 percent for
compliant commercial buildings, with
mandatory requirements for HVAC equipment
efficiency, controls, piping, and
ductwork.
[12]Indians experience heat 9 months of the
year, March to November. ACs run
year-round in cars and taxis. Yet the HVAC
systems installed in Indian commercial
buildings follow the same overhead
architecture designed for New York
winters. The design target is the room
volume, not the person.
ASHRAE Standard 55 (2023) defines thermal
comfort as the condition of mind
expressing satisfaction with the thermal
environment. Six factors: metabolic rate,
clothing insulation, air temperature,
radiant temperature, air speed, and
humidity.
[7] The adaptive model
recognises that occupants interact with
their environment. But the standard was
written around mechanical systems that
condition the full room volume from above.
Floor-level cooling systems, whether
mechanical or biological, sit outside the
standard's framework.
The economic cost is enormous. The
International Labour Organization
projected that heat stress would reduce
total global working hours by 2.2 percent
by 2030, equivalent to 80 million
full-time jobs. India was identified as
one of the hardest-hit countries, with
agriculture and construction absorbing the
majority of losses.
[13]The Lancet Countdown (2024) reported that
India lost 247 billion potential labour
hours to heat exposure in 2024, a record
high of nearly 420 hours per person. The
potential income loss reached $194
billion, with agriculture accounting for
66 percent and construction for 20
percent.
[19] These losses happen not in
extreme heat events, but in the ordinary
daily heat that Indian workers experience
9 months a year.
Biothermal Microconditioning addresses the
floor-level blindspot directly. Plant
clusters cool the occupied breathing zone
at 0.5 to 2 metres above floor level,
exactly where the person sits and works.
The building HVAC handles the bulk room
volume from above. The plant handles the
person from below. Two systems,
complementary, not competitive. Easy
Retrofit. 1 day.
