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AHU Systems — Evaporative & Hybrid Cooling

Air Handling Units built to run on 100% fresh air, not recirculated room air — from Degree Day’s D-Series and DX-Series ranges. Below: what each one does, real specs, and — at the end — a straight answer on which fits hospitals, hotels & banquets, and schools.

Not sure which AHU fits your space?

We run a free site survey and recommend D-Series, DX-Series, or a mixed layout — based on your building, footfall and season.

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Degree Day · D-Series

Dual-Stage Evaporative Cooling AHU

A high-performance double-skin AHU combining indirect and direct evaporative cooling. It draws 100% fresh outdoor air, cools it in two stages, and supplies it without adding refrigerant, compressors or recirculated air — an eco-friendly, low-running-cost alternative to conventional AC for dry and moderate climates.

Degree Day D-Series dual-stage evaporative cooling AHU unit
1

Fresh outdoor air in

~42–44°C
→
2

Sensible Heat Rejection coil (indirect stage)

30–32°C
→
3

Cellulose evaporative pad (direct stage)

18–20°C
→
4

Supply to conditioned space

22–24°C room, 55–65% RH
Airflow range1,000 – 40,000 CFM modular units · up to 200,000 CFM for built-up structures
Supply air temperatureAs low as 18°C, room temperature 22–24°C at 55–65% RH in peak summer
Power consumptionAs low as ~20% of a conventional AC system
Static pressure250 to 1,500 Pascals, selectable
Filtration20 micron to 0.3 micron options
Where it needs pairing: D-Series is built for dry and moderate climates. During Gorakhpur’s hot, humid monsoon spells, comfort settles around 28–30°C rather than tight AC-level control — for spaces that must hold comfort year-round, pair it with DX-Series or a spot AC.
Enquire about D-Series
Degree Day · DX-Series

Hybrid Evaporative + AC Cooling AHU

The DX-Series is Degree Day’s upgrade over the D-Series for mid-to-large spaces — a hybrid AHU that intelligently switches between evaporative cooling and full air-conditioning, sensing wet-bulb and room temperature, so one machine gives you year-round comfort instead of two separate systems.

Degree Day DX-Series hybrid AHU with outdoor AC condenser and cooling tower
Dry season

Evaporative cooling mode

Fresh-air circulation at the lowest possible running cost — the same low-power stage as D-Series, used whenever outdoor wet-bulb conditions allow it.

⇆Senses wet-bulb &
room temperature
Humid / monsoon

Air-conditioning mode

Switches over automatically in hot, humid conditions to deliver temperature-controlled comfort — can integrate with an existing chilled-water plant to cut costs further.

Enquire about DX-Series
Side by side

D-Series vs DX-Series

D-SeriesDX-Series
Cooling methodTwo-stage evaporative only (indirect + direct)Hybrid — evaporative + full AC, auto-switching
Best climate fitDry & moderate climates, peak Apr–Jun heatYear-round, including humid monsoon spells
Running costLowest — as low as ~20% of conventional ACLow on average — AC mode used only when needed
Comfort in humid weatherComfort settles ~28–30°CFull AC-level comfort maintained
Typical use hereSchools, back-of-house, dry-season crowd coolingHospital OPDs, hotel & banquet guest areas
Which series for your building

Hospitals, hotels & banquets, and schools

Hospitals

DX-Series for OPD & waiting areas, D-Series for back-of-house

Best fit: DX-Series for OPD halls, corridors and visitor waiting areas — it holds comfort through Gorakhpur’s humid monsoon spells, when a stand-alone evaporative unit would drift to 28–30°C.

D-Series works well for stores, laundry, staff and back-of-house zones, and is unbeatable on running cost through the dry, pre-monsoon heat of April–June.

OT, ICU and isolation areas still need dedicated medical-grade AC — these AHUs are for common and support areas, not critical care.

Hotels & Banquets

Both series clear food & crowd smell; DX-Series holds guest comfort

Either series solves the kitchen-and-crowd smell problem — 100% fresh air with no recirculation clears cooking odour from restaurants and banquet halls far better than recirculating split ACs.

DX-Series is the safer pick for guest-facing halls that must hold comfort through humid banquet season (Sept–Nov weddings); D-Series is the low-cost choice for the dry-season crowd.

Schools

D-Series is the natural fit for classrooms

D-Series suits classrooms and corridors well — lowest running cost (as low as ~20% of conventional AC), 100% fresh filtered air for growing lungs, and near-zero maintenance for institutional budgets.

Where the budget allows, DX-Series extends full comfort through the humid months too — useful for exam halls and admin blocks used year-round.

Specifications summarised from Degree Day’s published D-Series and DX-Series literature. Final unit sizing, static pressure and layout are engineered to your site after a free survey.

AHU systems — frequently asked questions

What is an AHU, and when do I need one instead of split or VRF units?

An Air Handling Unit (AHU) conditions and circulates large volumes of air through ducting, rather than cooling one room at a time. It's the standard choice for banquet halls, marriage lawns, auditoriums and hospital OPDs — any single open space too large or too tall for split/VRF indoor units to cool evenly.

Are Degree Day AHUs suitable for hospitals?

Yes — our D-Series and DX-Series both run on 100% fresh air, which matters for hospital OPDs and wards where recirculated air is a hygiene concern. Which series fits depends on the space's size, ceiling height and whether you need humidity control; that's confirmed on a site visit.

Which AHU series should I use for a banquet hall or marriage lawn?

Both series can work for banquet halls; the choice comes down to hall size, ceiling height and how many hours a day it runs at full occupancy. We compare D-Series and DX-Series against your actual hall dimensions rather than recommending one series across the board.

Do AHUs cost more to run than multiple split ACs for the same hall?

For a single large open space, an AHU is usually cheaper to run than covering the same area with many split units, since it moves conditioned air through ducting instead of running several separate compressors. We give you a running-cost estimate alongside the equipment quote.