FAQs

Q.
Why do I need a ventialtion system for my indoor pool ?
A.
Water eveoprates no matter what temperature or what condition it is in, it will eveoprate if left exposed. You can reduce the amount of evaporation by covering the pool when not in use but you can not eliminate it. If left uncovered the evaporation would produce high humidity's in the pool hall and promote mould and corrosion of the building structure.
Q.
Why can't I just open a window?
A.
You can but you will not get the correct amount of air that is required and you will not be able to hold the room temperature in the winter.
Q.
Can I just fit an extrator fan in the wall to ventilate the room?
A.
You can but the air that is extracted must be replaced and it will cost a lot of money to reheat the air that is drawn into the pool from outside.
Q.
Why should I buy a Recotherm ventilation system when I can protect the structure with a couple of fans and a heater battery?
A.
Recotherm have been building ventilation systems for indoor pools for 20 years and have refined there system so to reduce the running cost to as little as possible. A simple off the shelf ventilation unit would not be able to offer the energy saving features of the Recotherm unit and would not be able to with stand the corrosive effects of the swimming pool atmosphere. Recotherm have units in operation that have been running for 20 years.
Q.
Do I need a three phase electrical supply?
A.
No Recotherm have single phase units up to and including 2 m3/s which is large enough to accommodate a 200 m2 domestic pool.
Q.
Can the unit be installed outside?
A.
Yes the units can be weather proof for external use but the display panel must be sited internally or protected in a weatherproof box.
Q.
Can I site the display panel remote from the unit?
A.
Yes the display panel can be sited up to 800m from the unit and is connected by a core telephone style cable.
Q.
Should I fit a pool cover to the pool?
A.
A pool cover would reduce the evaporation from the pool, we would highly recommend a pool cover for domestic application where the pool is only in use for 1 to 2 hours a day. For commercial use the advantages are less clear you may wish to have the pool uncovered for aesthetic reasons or the hours of usage may be so long that the pool is only covered for a short period and getting your money back within the life of the cover may not be possible.
Q.
Can I reduce the air temperature when the pool cover is on?
A.
Yes because the pooled the evaporation is low and therefor reducing the air temperature will have only a minoe effect on the rate of evaporation. This can be linked into the Recotherm unit so that the temperature is automaticaly reduced when the pool cover is on.
Q.
Do I have the air temperature 1°C above the pool water temperature to avoid condensation?
A.
A.No this is a myth. Condensation occurs when air is in contact with a surface that is colder than the dew point of the air. The dew point of the air is a function of the temperature and humidity of the air. You can have the air temperature 5 °C below the pool temperature as long as the dew point of the air is below the temperature of the internal surfaces. The Recotherm unit controls the internal humidity and temperature and thus controls the dew point. With an external temperature of -1 °C and a room temperature of 30 °C a humidity of 50% will prevent condensation on a double glazed panel. If the air temperature was 25°C then a humidity of 55% would prevent condensation on a double glazed panel.
Q.
What governs the amount of evaporation from the swimming pool?
A.
The amount of evaporation from the pool surface is proportional to the difference in the vapour pressures of the air and the water it is also affected by the air movement above the pool and by the amount of activity in the pool i.e.A pool with high occupancy will have a higher evaporation rate than an unoccupied pool.
Q.
Can I control the pool water temperature from the Recotherm Unit?
A.
Yes we have spare capacity on the internal controller to monitor and control the temperature of the pool you will require a temperature sensor and control valve which are both available from Recotherm Ltd.
Q.
Does the unit come complete with all controls?
A.
Yes
Q.
Will I require an extra boiler to serve the ventilation unit?
A.
No the ventilation unit can usually be serve off the boiler that heats the pool water. This boiler should be sized to heat the water from cold to 30 °C in either 48 or 72 hours once it has got the pool water up to temperature there is usually spare capacity to supply the ventilation unit. You may require extra capacity on a commercial project depending on the rate of back wash.
Q.
How should the supply air be distributed?
A.
The air should be distributed in either metal or builders work ductwork and blown over the cold surfaces in the pool hall, this should mean the windows if you have any surfaces colder than the window then you should rectify the problem. The return air can be from a single point on one of the walls. (Please note the position of the return air grille has no effect on the distribution of the air) You should avoid blowing the air directly at the pool water surface as this promotes evaporation and will make the pool occupant feel cold.
Q.
I have a spa pool will this affect the unit I select.
A.
Yes a spa pool is at a high temperature than the pool and when in use is highly active you should let who ever is selecting the unit know that you have a spa and what size it is.
Q.
It isn’t possible to run ductwork up to my windows can I still avoid condensation
A.
It is possible to avoid condensation you will need specialist distribution grilles to throw the air to all corners of the room. You may also need to operate at a lower humidity because you are not covering the windows with dry warm air.
Q.
Can I run the unit from a 13 amp supply?
A.
You can operate the VF25, VF50 and VF100 from a 13 amp supply the bigger units will require a larger supply.
Q.
Do I need to have the unit running 24 hrs/day?
A.
Yes the unit is there to protect the building structure but if the hall is well insulated and you use a pool cover then the unit will slow down to it minimum speed and use only a small amount of electricity to power the return fan.
Q.
Do I need to have the boiler running 24 hrs/day?
A.
Yes to avoid excessive losses from the pool and prevent condensation we need to keep the temperature in the pool 24 hrs/day. It is therefore necessary to have the hot water from the boiler available on command.
Q.
I have been told I need a heat pump dehumidifier to control condensation is this correct?
A.
No a heat pump dehumidifier is just a different type of unit it works by recirculating the air and removing moisture in a direct expansion evaporator the heat from this process is then use to heat the air and water. Unfortunately the dehumidification process runs on electricity which is expensive and by recirculating the air without removing the chlorine and body odour smells it give a poor atmosphere in the pool hall. The Recotherm unit will give you a better atmosphere and cost less to operate.

 

 

 

 

 

 

 

 

 

 

 

HOW DOES IT WORK ?

FRESH IS BEST

Fresh Air Ventilation
To understand how fresh air ventilation can work it may be useful to look at the properties of air.

The air around us has moisture content. That is, it contains so many grams of water for every kilogram of air. The amount of water the air can hold is dependent on the temperature of the air.

Air at 0°C has a maximum moisture content of 3.8g/kg. If it contained that amount of water it would be said to be saturated i.e. 100% relative humidity

It is important to appreciate that the term is relative humidity, and that it is relative to temperature. If the air was heated from 0°C to 15°C the relative humidity for the same moisture content would be 35% RH.

So you can work out for yourselves that air at 0°C 100%RH would actually contain less moisture than air at 15°C 50%RH.

The moisture content inside a swimming pool hall is very much higher than the fresh air. To give you an example, a typical pool with an air temperature of 30°C and relative humidity of 60% has a moisture content of 16.3g/kg.

In the middle of the winter, on a cold day, the moisture content would be 3.8g/kg. On those wet days in April the moisture content would be 10.2g/kg and on a summer day the moisture content is only 11g/kg.
By introducing fresh air at any of these conditions it will lower the moisture content and thus the relative humidity within the pool hall.

But if you were to introduce the fresh air without any sort of control then the running cost for the system would be extremely high, so what you need to do is to introduce the precise amount of fresh air that is required and no more. This is what Recotherm have done with the VF unit.

The unit combines a number of energy saving techniques to reduce the overall energy bill.

To recover the heat in the outgoing exhaust air there is a HEAT RECUPERATOR.
This is a passive heat exchanger , there is no energy input to this unit. It picks up the heat in the exhaust air stream and transfers this into the fresh air stream over a series of aluminium plates. Typical efficiencies for these exchangers are 60%, so if the exhaust air is going out at 30°C and the fresh air is coming in at 0°C we will heat the air to 18°C.
To reduce the electrical consumption there are HIGH EFFICIENCY FANS.
The fans used in the unit are direct driven, which instantly gives a saving of 15% because there are no belt and pulley losses that you get with indirect fans. They also maintain a constant rate of air unlike belted systems whose supply air rate drops off as belt stretches. The blades on the fan are backward curved which will give an extra 10% saving over forward curved fans.
To control the unit there are MICROPROCESSOR CONTROLS.
Sensors mounted in the return air chamber send back to the controller the temperature and humidity reading every five seconds. Using this information, the controller decides on the amount of air and heat that is required along with how much recirculation that can be permitted. This gives precise control over the internal conditions within the pool hall and ensures that the unit is not working any harder than it needs to thereby keeping running cost to a minimum..

To control the air volume there are FREQUENCY INVERTERS.
Frequency inverters change frequency of the electrical supply to the motor. this reduces the speed of the motor and thus the speed of the fan. The slower the fan runs the lower the air volume. Thus by controlling the frequency inverters precise control is gained of the air volume.

By controlling the air volume the exact amount of fresh air that is required can be introduced so minimising the heating load. But there is an even better reason for using the inverters. The lower the air volume, the lower the power consumption. Not as you may expect a 20% reduction in air volume giving a 20% reduction in power consumption. NO a 20% reduction in air volume will give a 50% saving in power consumption.

Recotherm utilises frequency inverters on a swimming pool ventilation system because the air volume is calculated to cope with the maximum dehumidification load but for majority of the time the maximum dehumidification is not required. Hence we can use a lower air volume.
So you can see what Recotherm have done is to design a unit using conventional heat recovery techniques, combined with high efficiency fans driven by frequency inverters and all controlled using the latest microprocessor technology.

What this gives you, the customer, is the most economical way of controlling the swimming pool environment without compromising the quality of that environment.