In-floor heating - Fan coil units (FCU)What are Heat Pumps?Heat Pump applicationsSuggested Heating / Cooling Solutions
In-floor heating – Fan coil units (FCU)
In-floor Heating
How is in-floor heating constructed and operated?
In-floor heating is constructed by laying tubing on the floor and covering it with a special layer of concrete in order for the whole construction to function as a large “radiator”. Throughout this system, hot water of 35-45 °C circulates inside a piping circuit that is integrated into the floor of the room, transforming the floor itself into a radiator.
The heat transmission is carried out by radiation from the floor to the heated space, from the lower layers to the higher over the entire surface of the space without strong currents. This achieves the desired temperature stratification, that is the temperature rises to 18-20 °C at head level. Heating through the piping circuit that runs through the entire surface of the space ensures the basic requirements of modern life, that is comfortable and healthy living in thermal comfort. One can easily enjoy unrestricted aesthetics in a contemporary modern residence and environmental friendliness, while saving energy and money thanks to in-floor heating!
What are the advantages of the in-floor heating – heat pump system?
- Ideal thermal comfort conditions with mild heat transfer, thermal energy flow from feet to head, temperature uniformity throughout the areas.
- Energy saving & low operating costs because it works with low water temperatures (35-45 °C).
- Flexibility in architectural configuration of the premises because there are no radiators or other terminal units.
- Cooling mode for the summer months using the same system.
Fan coil units
FCUs or otherwise known forced circulation units are indoor units that are supplied with water at a proper temperature and, in this way, transfer heat or cooling to the various spaces.
As far as design is concerned, there is no difference at all compared to conventional air conditioners. Depending on the space, the architecture and the decoration, there are various types of FCUs, such as wall-mounted, floor exposed, floor concealed for canals, ceiling exposed, ceiling concealed for canals and cassettes. The only difference of conventional air conditioners is that freon goes through their inverter whereas fan coil units have chilled water. This way, when provided with hot or cold water from the heat pump, fan coil units give us cooling and heating in a similar way as and with a similar feeling of a room air conditioner.
The FCUs receive water at a lower temperature, however, between 35 °C and 50 °C. Then, the fan distributes heat to the area, unlike the simple radiators where the heat distribution is done naturally and through extraction, without the use of a fan.
What are Heat Pumps?
A heat pump is a great achievement of 20th century engineering. It is a simple device, which has high efficiency and provides heating or cooling by consuming electricity. Its function is based on the Carnot cycle. There is a cooling circuit in the heat pump. The greatest advantage of heat pumps is that they exploit the heat that is already present in the environment. The heat pump works in exactly the same way as an air conditioner during the summer to provide cooling.
Heat Pumps can be installed in new or old buildings and can be connected to existing or new radiators, with in-floor heating as well as to FCUs. For greater energy and cost saving, they can also be connected to solar panels, as well as use home-produced electricity from photovoltaics.
Advantages of Heat Pumps
- Protection of the environment. Heat Pumps are the cleanest form of energy with the lowest possible burden on the environment in our time.
- Energy saving. Heat Pumps can be up to 6 times more efficient than traditional heating systems. The average annual efficiency rating of the system in our country, during ideal climatic conditions, may be over 4 for air-to-water pumps, ensuring a high rate of efficiency with minimal operating costs.
- Installation location. Heat Pumps can be installed easily outside or inside the house. They can ideally heat and cool the whole house, without the need for a boiler room, chimneys, ventilators and fuel tanks. Installation is carried out after a relevant study of the exterior or interior space available depending on each case.
- Maintenance cost. Heat pumps do not need maintenance every year, as is the case with oil, gas and pellet boilers. Their operation has minimal maintenance costs.
Heat Pump energy efficiency and energy consumption
With heat pumps, we pay the transport cost rather than the energy production cost.
The transport cost is a percentage of the cost of the transferred energy and is measured using the COP indicator (for heating) and the EER indicator (for cooling).
Both indices are defined by the fraction of energy transferred / energy consumed.
When we say that a heat pump has a COP 3 indicator, it means that for each kilowatt hour the device consumes, we carry 3 kilowatts of energy.
These indicators are instantaneous and refer to specific environment temperature, room temperature and water temperature conditions. For the indicators to be comparable between models and manufacturers, they are measured in standard conditions that have been standardized by Eurovent.
In addition to the aforementioned indicators, SCOP and SEER indicators are also used for the assessment and the energy classification of heat pumps. These indicators are designated as “annual energy consumption and efficiency” in heating and cooling respectively.
When we say that a pump has an annual SCOP 4 performance level, this means that for one year, this pump will consume 1kWh and deliver 4kWh in our space on average.
Since our country has a very hot climate, the seasonal indicators are greater than 4. How greater they are depends on the model and the brand of the manufacturer.
Heat Pump applications
Θέρμανση χώρων
Κατά τη χειμερινή τους λειτουργία, οι αντλίες θερμότητας αντλούν την ενέργεια από το ψυχρό περιβάλλον και την μεταφέρουν στον θερμότερο χώρο μας, διατηρώντας έτσι ή αυξάνοντας την θερμοκρασία στο εσωτερικό του σπιτιού.
Ψύξη χώρων
Κατά τη καλοκαιρινή λειτουργία, οι αντλίες θερμότητας αντλούν την ενέργεια από το εσωτερικό του χώρου μας και την μεταφέρουν στον θερμότερο περιβάλλον, διατηρώντας έτσι το σπίτι μας δροσερό.
Απαραίτητη προϋπόθεση για τη δυνατότητα ψύξης είναι η αντλία να είναι συνδεδεμένη είτε με ενδοδαπέδιο σύστημα (ενδοδαπέδιος δροσισμός) είτε με κλιματιστικά νερού (FCU). Δεν είναι δυνατή η λειτουργία ψύξης με κλασικά θερμαντικά σώματα.
Ζεστό νερό χρήσης
Η σύνδεση μιας αντλίας θερμότητας με ηλιακό θερμοσύφωνα ζεστού νερού χρήσης, καθιστά δυνατή τη θέρμανση ΖΝΧ με τη χρήση της αντλίας θερμότητας.
Η σύνδεση αυτή μπορεί να γίνει είτε σε συνδυασμό με σύστημα θέρμανσης (οπότε η αντλία θερμότητας λειτουργεί τόσο για να θερμάνει τόσο τον χώρο μας όσο και το νερό χρήσης) είτε αποκλειστικά για την θέρμανση ζεστού νερού χρήσης.
Suggested Heating / Cooling Solutions
I. Heat Pump with In-floor Heating and Cooling with Ceiling Concealed Chilled Water FCU
The heating and cooling system we offer consists of an air / water heat pump, the in-floor heating and cooling system and the network with the FCUs used for cooling and rapid heating. Using the hot or cold water that the heat pump produces, we use the in-floor heating that is a low temperature heating system as the main space heating device and we meet the need of wanting a system that responds faster than in-floor heating along with the FCUs. During the summer, FCUs provide cooling with the same features of autonomy and similar noise levels of an advanced state-of-the-art home air conditioner without having an outdoor unit.
With the appropriate thermostat, each FCU is fully autonomous both in operation and settings and can function alongside or independently of the in-floor heating or cooling, which also have room autonomy upon request. In order for the system to operate successfully, efficiently and without using a bulky buffer tank, it is necessary that the pump
be an inverter, in other words, of reduced efficiency. Apart from the cooling needs, FCUs meet the need of wanting quick heating to absorb humidity during the season when we still do not need main heating.
II. Heat Pump for heating and cooling with ultra-thin fan coil units (FCU) (floor)
The newly designed ultra-thin fan coil units (FCUs) have a smaller and more elegant unit and can be the best decoration for your rooms. The performance of such units is as satisfying as the one of classic units, while they have a compact construction and a scientific design. All these features can give your family an exceptional quality of life. Key features: Small size 13 cm wide for easy installation in small spaces, 30% reduction in consumption.
Our ultra-thin fan coil units (FCUs) are based on the forced convection heat transfer function which makes heat dissipation more efficient. Fan coil units outmatch classic radiators by 30% in saving energy. The state-of-the-art controller offers an equal temperature distribution, providing comfort throughout the house. Connecting the FCUs to the heat pump gives us heating or cooling depending on the season with a minimum noise level.
III. Heat pump and radiators
Often, it is said that heat pumps operate only with in-floor heating systems. This is not true. Heat pumps work very well with radiators, provided that the system has been properly designed.
What is true is that the heat pump will be more effective when the temperature of the water that it heats is kept as low as possible. It is also true that good in-floor heating systems are designed to operate at low temperatures as opposed to radiators. However, not all in-floor heating systems are properly designed, and, in such cases, they may be less efficient than radiators.
Radiators that are connected to a heat pump should be large enough to be able to deliver enough heat at temperatures of around 50-55 °C, temperatures at which heat pumps are effective. This is sometimes described as “over-dimensioning” of radiators.
So, when we install a heat pump in a house, the first stage of our design process involves a survey of the house and its radiators to determine whether changes need to be made to their dimensioning.
Note: when radiators are sold, they are described using the output value in kW. This is the amount of thermal power to be extracted at a flow temperature of about 70 °C. If the flow temperature drops to about 50 – 55 °C, the radiators will continue to work perfectly but will produce less heat. Thus, in order to get the same output power at the lowest temperature, the radiator must be larger.
