R&D brief - air conditioning and ventilation for hot humid climates¶
ARC's technical brief for a prototype air-conditioning unit that balances cooling against dehumidification and supplies fresh air without a large energy penalty.
This is a brief, not guidance
This page describes work ARC would like done. It is not a specification for equipment you can buy today, and nothing here has been built or tested.
1. Objective¶
Develop a prototype air-conditioning unit optimised for high-temperature, high-humidity environments such as those found in parts of Tanzania and similar regions. The system should:
- cool indoor air effectively
- remove excess humidity efficiently
- introduce fresh outdoor air with minimal added energy load
- operate reliably with minimal maintenance and energy input.
2. Core design challenge¶
In hot and humid climates, thermal comfort depends on both temperature reduction and moisture removal - see what influences thermal comfort.
Standard air-conditioning units often either:
- overcool air in order to achieve dehumidification, wasting energy; or
- fail to adequately remove humidity, leading to discomfort and mould growth.
The design must balance cooling and dehumidification efficiently. This is the same requirement placed on Zone 1 spaces.
3. R&D focus areas¶
A. Cooling and dehumidification balance¶
- Design for independent control of temperature (sensible load) and humidity (latent load).
- Investigate two-stage cooling systems:
- Stage 1: moisture removal using cold coils or desiccant systems
- Stage 2: reheat, to deliver comfortable air supply temperature.
- Use variable-speed fans and compressors for energy-efficient modulation.
Target performance
| Measure | Target |
|---|---|
| Indoor air temperature | 26–28 °C |
| Relative humidity | 50–60% |
| Energy use | Lower than typical single-stage systems |
B. Fresh air ventilation with low energy penalty¶
Fresh air is essential for indoor air quality, but increases the cooling and dehumidification load.
Options
- Integrated into the AC unit - heat and moisture recovery ventilators (HMRVs), or desiccant-based intake systems.
- Separate systems - trickle vents, possibly with moisture control features; stand-alone energy recovery ventilators (ERVs); solar-powered extract.
Ventilation target - supply 10–20 m³/h per person of fresh air, while minimising additional cooling and moisture load.
4. Context and practical constraints¶
Environmental conditions
- Outdoor air: 30–35 °C, 70–90% relative humidity
- Power supply: intermittent or expensive
- Maintenance: should be low-frequency and simple
- Noise: quiet operation preferred in domestic spaces.
Materials and build
- Corrosion-resistant components
- Modular, repairable parts
- Suitable for potential local assembly in East Africa.
This reflects the wider ARC principle of simple, robust, locally repairable equipment - see designing a heat refuge.
5. Outputs required¶
- Concept drawings and control schematics
- Thermal and energy performance simulations
- Bill of materials with approximate costing
- Working prototype for field testing
- Maintenance and installation guides suitable for non-specialist users.
6. Success criteria¶
- Indoor climate: 26–28 °C, 50–60% relative humidity
- Fresh air provision: 10–20 m³/h per person
- Energy use: at least 30% less than conventional air conditioning
- Ease of use and maintenance
- Robustness and reliability in local conditions.
Source: ARC Technical Criteria - Appendix 3: technical R&D brief
Reference · confidence medium · Imported 2026-08-29, not yet reviewed · next review 2026-11-29
Tags: research, air-conditioning, ventilation, dehumidification, brief
Citation key: cooling-rd-brief