What is a heat pump and how does it work?
In a heat pump, cooling and heating are combined in a single heat engine. In winter it obtains heat from a medium at a low temperature (outside) and transfers it to another that is at a higher temperature (inside). In summer, it performs the usual cycle of a chiller, transferring the heat from a low-temperature source (the place you want to air-condition) to a high-temperature source (outside the building). Heat pumps are often referred to as an outdoor unit and an indoor unit instead of a condenser and evaporator. It acts according to the external conditions.
The interesting thing about the heat pump is that the amount of energy consumed in making the compressor work is small compared to the energy given off by the condenser. Comparing the power supplied to the compressor with the energy of the electric heating by the Joule effect, the heat pump supplies 4 times more useful heat, with the energy savings that this implies.
Goodman – pros and cons
Goodman isn’t renowned as the best heat pump on the market for nothing. It offers property owners a wide variety of benefits towards an efficient heating and cooling functionality. Below are some of the advantages and disadvantages of buying a Goodman heat pump.
- Goodman has single unit models that cover all the heating, cooling, and domestic hot water needs of the home.
- Its models are especially suitable for new construction and comprehensive rehabilitation of buildings.
- Goodman products require very little maintenance.
- It makes use of low-risk energy when compared to flammable fuels.
- A Goodman heat pump is a good option in places where fuels such as gas or diesel are not available.
- Its products are certified and approved by industry regulators and institutes.
- Goodman heat pumps are a bit hard to install. This requires the service of a registered and certified installer.
- Goodman doesn’t approve self-installation. So, it’s not a toy for DIY enthusiasts, or else, you’ll void the warranty.
Features to consider before you buy a Goodman heat pump
There are some important features to consider before buying a Goodman heat pump. From the EER and SEER ratings, HSPF, noise level, to the compressor, here we analyze them in full.
First we should consider the existing types of the heating pumps:
Heat pumps according to construction
Depending on the way in which the equipment is built, it can be:
- Compact: All the parts of the system are inside the same casing. A good example is the Goodman GPH14M.
- Split: They have two separate components, the indoor unit and the outdoor unit where the compressor and the expansion valve are housed. The two parts are separated in order to avoid noise inside the cabin. A good example is the Goodman GSZ140361- ARUF37D14.
- Multi-split: They consist of several indoor units connected to one outdoor unit.
Heat pumps according to the source and medium of energy
- Air-to-air heat pumps: They are the most used in general, and their main function is to transform the air from one temperature to another.
- Water-air heat pumps: They take advantage of the energy contained in the water of rivers, seas, and waste.
- Air-water heat pumps: They extract free energy from the outside air to convert it into cold, heat, and sanitary water.
- Water-water heat pumps: They extract heat for groundwater heating with low-temperature radiators, fan coil units, or underfloor heating.
- Ground-to-air heat pumps: They use the natural properties of the earth to provide heat and cold to a building.
- Ground-water heat pumps: They take advantage of the heat contained in the ground and through condensation by water they provide heat or cold to the building. They are unusual due to the cost of the facilities.
Heat pumps according to operation
- Reversible: They have the possibility of working both to heat an environment and to cool it. This is thanks to the fact that it can reverse the direction of the flow of the refrigerant fluid thanks to a valve.
- Not reversible: They only have the possibility of working in the heating cycle.
The dimensions of your heat pump are important, especially when you don’t have enough space. However, the good thing about Goodman models is that you can find compact models with equal functionality of bigger or split heat pumps. The average dimension of a heat pump is usually in 22″ Height, 32″ Width, and 1′ Depth. This dimension is smaller than an average air conditioning condenser.
EER and SEER ratings
The Energy Efficiency Ratio (EER) and Seasonal Energy Efficiency Ratio (SEER) are all energy performance parameters. They allow us to know the energy efficiency of a heat pump. These coefficients relate the amount of energy to be contributed to the system, that is, consumption, with the heat or cooling obtained from it. There is also the Coefficient of Performance (COP). This is the expression of the energy efficiency of a heat pump. In other words, it is the relationship between the power (kW) that comes out of it and the power (kW) that is supplied to the compressor that produces that heat.
The energy efficiency index or Energy Efficiency Ratio (EER) also measures the relationship between the electrical energy consumed and the total power a heat pump generates. In 2013, Commission Delegated Regulation (EU) No. 626/2011 entered into force on the energy labeling of HVAC equipment. This fact meant a change in the denomination of the parameters that measure the energy efficiency of these devices. Thus, the current name is Seasonal Coefficient Of Performance (SCOP) and Seasonal Energy Efficiency Ratio (SEER).
In addition, from that moment on, the information that the labels must include that can be consulted in Annex III of said law was established. In this way, if your equipment is prior to 2013, the COP and EER parameters will be indicated, but if they are later, they will be SCOP and SEER. The EER and SEER parameters refer to the efficiency of the equipment in cold production, that is, refrigeration; and the COP and SCOP parameters refer to the energy efficiency of the equipment in heat production, that is, heating. The higher they are, the better the efficiency of the equipment, and generally its price will be higher.
The interesting thing is to find the balance between the ratio and the price. In the long term, cheap equipment with a very low SEER will be less efficient.
The basic difference between the EER-COP and the SEER-SCOP is that the latter are seasonal. The EER and the COP measure power under certain environmental conditions operating at full load; while SEER and SCOP measure seasonal energy performance taking into account:
- The amount of energy, both heating and cooling, that is produced during normal use of one year divided by the total electrical energy consumption in the same period.
- The measurements that are most representative of the actual use of the equipment, which are the partial loads of 100%, 74%, 47%, and 21%.
- The consumption of the equipment when it is off, deactivated by a thermostat, or in standby. This is what is known as “phantom/standby consumption”.
Where to find the SEER of your heat pump
In the event that you cannot find the data for the seasonal average yield (SCOP and SEER), you can find the default nominals, that is, COP and EER. But here are some tips to help you find them:
- First, check the EnergyGuide sticker that is usually in yellow and black in the outside part of the unit. This label usually displays the HSPF, EER, and/or SEER ratings.
- In case it is not found in the label or sticker, look for the model of the device on the internet. The technical sheets with all the information you need usually appear on the supplier’s official website.
What is the best SEER and HSPF rating for a heat pump?
The American Council for an Energy-Efficient Economy (ACEEE) recommends SEER rating of at least 15 and an HSPF of at least 8.5. However, for Goodman models, the most energy-efficient are Goodman 18 seer heat pumps. While a Goodman 16 SEER heat pump meets the recommendation of ACEEE, the Goodman GSZ140361, GSZ140301, and GPH14M all come close to that number with SEER rating of 14.
BTUs and CFM
As mentioned in the product review, the BTU stands for British thermal units. Meanwhile, the CFM stands for cubic feet per minute. To choose the right BTU and CFM, choose a model with a CFM of 350-450 per 12000 BTU per hour capacity. Choose a model with at least 750 CFM for every 12000 BTU per hour across outdoor coils.
The heat pump compressor is an element that consumes mechanical energy for its operation. Its function is to increase the pressure of the refrigerant in the gaseous state, coming from the evaporator to a pressure that transforms that gas into a liquid. Depending on how the motor is coupled with the compressor there are different types:
- Hermetic: Motor and compressor on the same shaft and casing. For powers less than 70 kW.
- Semi-hermetic: Same axis. Part of the heat generated by the engine is recovered in the coolant. For medium powers.
- Open: Independent belt-coupled motor and compressor. It is used in large installations.
The good thing about Goodman heat pumps is that they are ultraquiet. The GSZ line which the Goodman GSZ140361 and the Goodman GSZ140301 belong to emit noise level between 72-76 decibels. They have condenser fans which give good cooling effects and quiet air movement through the coils and blades.
Heat pumps accessories
There are other accessories that accompany the heat pump so that its refrigerant circuit remains in an optimal state. They are classified according to the pressure of the area where they are. In an installation, there are two main zones depending on the state of the refrigerant:
- Liquid or high-pressure zone.
- Gas or low-pressure zone.
The following elements are found in the high-pressure zone of heat pumps:
- Discharge silencer: dampens the noise at the compressor outlet.
- Vibration damper: network piping system vibration damper.
- Liquid container: accumulator for the coolant.
- Bleeder: used to expel the air from the refrigerant circuit.
- Filter drier: removes moisture from the refrigeration circuit.
In the low-pressure part, the following stand out:
- Oil filter: filter for cleaning the oil that returns to the compressor.
- Liquid separator: removes refrigerant fluid droplets so that gas only enters the compressor.
- Liquid accumulator: prevents water hammer in the compressor.
- Crankcase electrical resistance: electrical resistance in the compressor to avoid mixing the oil in the crankcase with refrigerant liquid, a circumstance that occurs at low outside temperatures.
- Oil separator: maintains the oil level of the compressor and that it enters the compressor or evaporator.
- Heat economizer: heat exchanger at the outlet of the evaporator and condenser that increases the performance of the heat pump.
- Solenoid valve: serves to control the amount of refrigerant that goes to the evaporator through an electrical control made up of a solenoid coil.
- Check valve: elements that allow the circulation of fluid only in one direction. They are used to avoid unwanted returns.
The different certifications and regulations are indicators of quality, efficacy, and safety.
- ETL certification: This is a certification that is issued by testing company Intertek’s Electrical Testing Labs (ETL). Nationally recognized in the US, the certification is a mark that products with the mark are safe for use in living and working environments. The Goodman GSZ140361- ARUF37D14 is an example of an ETL-certified heat pump.
- CE marking: The CE mark is a mandatory self-declaration that commits the manufacturer to take responsibility for personal safety. It indicates a product’s conformity with safety, environmental, and health protection standards.
- Eurovent: Eurovent certification, which applies to manufacturers, is only applicable in reversible air-to-water heat pumps. It guarantees the performance indicated by the manufacturers.