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We answer your questions.

In this section you will find the answers to your questions.

Our product engineers have created a series of documents that will try to clarify in a clear, precise and concise way, all your doubts related to our technology and our products.

If, on the other hand, you haven't found the answers you were looking for, contact us directly and we'll try to address your needs.

Gas Absorption Heat Pumps

What are Gas Absorption Heat Pumps?

Gas Absorption Heat Pumps combine the advantages of the two most common heating technologies: gas boilers and electric heat pumps.
They offer all the advantages of boilers because:

  1. they are fired by natural or propane gas;
  2. they don’t use any refrigerants harmful to the environment;
  3. they are easy to install.

They also offer all the advantages of electric heat pumps because:

  1. they use renewable energy (such as air, ground and water);
  2. they can supply chilled water for cooling in summer and hot water for heating in the winter (reversible type);
  3. they are suitable for outdoor installation and they don’t need mechanical room (air-source).

How do gas absorption heat pumps work?

The operating principle is similar to traditional electric heat pumps. The main differences are:

  1. the use of a gas burner instead of an electric compressor;
  2. the use of a water-ammonia solution instead of a refrigerant harmful to the environment, as is the case of most electric heat pumps.

Does the heating efficiency of the air-source heat pumps vary according to the outdoor temperature?

As for all the heat pumps, the heating capacity is affected by the energy absorbed from the environment.

The colder the environment, the less energy absorbed and the lower the efficiency.

However, Robur’s Gas Fired Absorption Heat Pumps are affected less by outdoor conditions than electric heat pumps.

Actually, the efficiency of Gas Absorption Heat Pumps decreases moderately as the external temperature decreases.

Gas Absorption Heat Pumps can operate down to -20°F and provide efficiency higher than 100% down to -4°F.

What is the highest temperature of hot water supplied?

Hot water temperatures are key parameters when designing systems with heat pumps. Robur Gas Fired Absorption Heat Pumps can supply hot water up to 140°F, a temperature higher than the majority of electric heat pumps and they can be easily integrated with existing (retrofit installation) or new boilers (new constructions).

At low external temperatures, what are the efficiencies of the air-water gas absorption heat pumps?

These appliances are designed to be installed outdoors.

They are fully weatherproof and capable of stable operation down to -20°F.

Even during the unit’s defrost cycle (typically when outdoor temperatures are below 32°F and the air is humid), Robur heat pumps are capable of providing approximately 60% of its rated heating capacity.

Defrosting takes only a few minutes and the energy necessary is negligible.

As these are air source units the heat energy available will reduce as the outdoor ambient lowers.

Is back-up/emergency heat required with Robur heat pumps?

The Robur air-water heat pump systems are capable of operating down to -20°F, which is much lower than the typical electric heat pump.

However, as the ambient temperature lowers so will the heat energy available and thus a lower system capacity.

Depending on your design temperature and the lowest expected ambient for your area, a back-up heating system may be required.

However, it may be used only a very small portion of the time with a Robur heat pump as compared with an electric heat pump.

Are Robur gas absorption heat pumps certified for selling in North America?

Robur Gas Absorption Heat Pumps were introduced to the US market in 2006.

They are CSA approved, CEC (California Energy Commission) listed and recognized by the DOE.

Do the gas absorption heat pumps improve the energy efficiency class of the building?

Yes, they do.

The energy efficiency class of the building is affected by its total energy consumption.

Actually, the less energy required for heating, the higher the energy efficiency class of the building.

This allows for an improved property value when compared to other heating appliances.

What are the main differences between the installation of gas absorption heat pumps and boilers?

Actually, there are no differences, except the advantages of the outdoor installation and no need for a large indoor equipment room.

The gas supply and hot water distribution system is similar for both; while the Gas Fired Absorption Heat Pump can have heating efficiencies up to 40% higher than condensing boilers with proportional energy savings.

What maintenance operations are recommended for gas absorption heat pumps?

Maintenance operations are similar to gas boilers and recommended annually.

What is the efficiency rating (SEER) of a Robur unit?

Appliances using gas as their primary energy source are rated differently than electric cooling and heating equipment.

Robur’s air source heat pump offers the highest heating efficiency of any gas appliance on the market.

At nominal conditions the heat energy of the unit’s absorption cycle combined with the heat extracted from the outdoor air is approximately 126% (Input of 95,500 btu/hr ÷ Output of 120,400 Btu/hr).

How does the efficiency of a Robur heat pump compare to an electric air to air heat pump?

Gas absorption heat pump efficiencies cannot be directly compared to electric heat pump efficiencies.

As an example, Robur’s heat pumps are rated with a G.U.E. (Gas Utilization Efficiency) while electric heat pumps are rate with a C.O.P. (Coefficient of Performance).

Where do I vent the indoor heat pump?

The Robur GAHP-W & W-LB heat pump models are designed for weather protected or indoor installation.

The units are classified as Category III appliances per CSA equipment approvals and must be installed in accordance to International and local codes that apply to Category III appliances.

Additional information is provided in the unit’s installation manual for venting the appliance to the outdoors with an approved Class III vent pipe.

What do you do with the outdoor flue on the Robur air source heat pump (models GAHP-A & AR) when the outdoor temperatures are below freezing?

In climates that experience freezing temperatures, the small plastic drain tube on the bottom of the vent pipe must be removed to avoid ice accumulation in the lower portion of the flue pipe.

How close to a business or home do the outdoor chiller and air source heat pump units need to be placed?

All units have minimum clearances that must be observed. 18” on the sides, 24” at the rear and 36” at the front.

Also, they must not be located under eaves or roof drip lines, however, because these units are hydronic systems (Chilled and/or hot water) they may be located long distances from the building to be conditioned if insulated properly.

Water lines and pumps must be sized accordingly to accommodate any distance.

What are some of the advantages of a Robur unit?

Zoning capabilities, smaller electric service in the building, lower electric consumption, environmentally friendly, quiet operation, long life, no compressors, lower operational cost and more.

Will a brown out or power outage affect the operation of the unit?

With the aid of a back-up generator, the Robur unit can still operate through a black out. Because the unit’s primary energy source is gas, the size of the back-up generator necessary for operation is considerably smaller (about 75% less) than one required for an electric cooling unit.