Want to Save Energy from your Air Conditioning? Improve the Ventilation with a hybrid AHU

Of Course you want to save energy — that’s a given, but where do you start? Everyone knows that A/C systems are the largest consumers of energy especially VRF and Chilled water systems that use Fan Coils to provide cooling/heating to the occupied space. So what can you do to the air conditioning to save energy?

Saving energy from the A/C equipment should be easy especially when you take into account the varying occupancy with hybrid working.

One key factor that is often overlooked and not always understood is the ventilation system. Ventilation in simple terms is often simply providing basic supply/extract air to/from the occupied space.

By replacing conventional Air Handling units with a new latest generation Hybrid unit (one that offers up to 100% fresh air plus heat recovery and Heating/Cooling and Dehumidification) means a correctly sized Hybrid ventilation is able to compensate for the latent and sensible loads. Humidity control is the key here. The Damvent Hybrid AHU’s deal with these automatically to save energy, but first lets explain what latent and sensible loads are:

Latent and Sensible Cooling

Sensible cooling load involves lowering the temperature of air provided to a space without causing the moisture in the air to undergo a phase change and condense. On the other hand, latent cooling is responsible for dehumidifying the air by producing a phase change and causing condensation to occur.

Latent and Sensible Heating

However in heating terms its heat that causes a change in temperature is considered sensible heat. Heat that causes a change in moisture levels is considered latent heat. Dehumidifiers remove latent heat and air-conditioning units remove sensible heat.

The Damvent Hybrid units that we offer are able to take a large chunk of the heating/cooling loads in a building without the high costs of an expensive Chiller or VRF system. This also means that when combined with one of these systems that they can be sized smaller with reduced cost.

Suitable for Every Climate — from -25°C to +60°C

Every Application — suitable for every application where 100% fresh air is needed, and includes:

• Filtration
• Recirculation — 0÷100%
• Heat recovery
• Heating
• Cooling + Dehumidification
• Process Ventilation

Suits Every Installation location — for mounting either indoor and outdoors.

Recovers up to 100% of the extract heating/cooling, achieved — “consecutively” in 2 stages:

1st stage — the rotary heat exchanger, recovers more than 70% of the heating/cooling and humidity.

2nd stage -the evaporator/condenser of the inbuilt air to air heat pump, recovers the rest up to 100%.

It’s a multifunctional solution for fresh air (as well as for covering heating losses and cooling loads at once), which can practically solve entirely the need for Air-Conditioning, Ventilation and Heating by using only the air as fluid. Thus, radiators/fan coils/cassettes, boilers, chillers/VRF systems, piping, insulation, pumps, fittings, etc., are reduced. It only needs a duct system.

Have a look at the COP/COPNET Data below.

COP/COPNET Air Conditioning to save energy.

The Damvent units are higher than the highest standard

A conventional air-cooled heat pump uses the ambient air for the evaporation process, and during the winter, this air can reach temperatures of -10°C, -15°C or even -20°C.

Extracting heat from the ambient air is an inefficient process. In comparison, the Damvent Max.e units uses the extract air from within the room. Under normal conditions, this air ranges in temperatures from 20–24°C. Firstly, 65–80% of the heat is recovered in the rotary/plate heat exchanger and then at a temperature between 1–6°C, the air enters the evaporator of the heat pump, thus recovering the other 20–35%.

Using this method, we achieve a COPsystem of 10 and avoid frost formation on the evaporator (which commonly occurs in all conventional heat pumps).

COPnet = Qplate/rotary heat exchanger + Qheat pump

Nfans+ Ncompressor

Where:

1. Qplate/rotary heat exchanger — recovered heat in the rotary heat exchanger (kW)

2. Qheat pump — heating capacity of the condenser of the heat pump (kW)

3. Nfans — energy consumption of both (supply and exhaust) fans (kW)

4. Ncompressors — energy consumption of the compressors (kW)

By improving the ventilation system with hybrid AHU’s a large part of the load is taken away from the main Cooling/Heating plant.

Originally published on Specifier Review