NU-1500 High Efficiency HRV Pool Unit For Small Natatoriums

NU-1500 High Efficiency HRV Pool Unit for small pools The NU-1500 HRV Pool Unit is a high efficiency energy recovery pool dehumidification system which is field erected on-site. All of the components fir thru a 36″ wide standard door. It has been designed with the latest state-of-the-art materials. Each component has been selectively designed to work to enhance the maximum energy performance as required for small indoor natatoriums.
Until now, it has been very expensive to bring into the pool room large amounts of outside air to detoxify the environment. Indoor natatoriums typically require the use of very expensive HVAC equipment to operate the pool environment within humidity levels that can reduce building damage and create a safe environment for the swimmers. Pool air temperatures are required to be elevated 1 to 2 degrees above the pool water temperature to achieve this objective. The evaporation rates off the pool surface vary up and down with the pool activity level. Outside air is a great oxidant and is a helpful deodorant for use in an indoor natatorium.

Standard designs of the past used a refrigerant compressor to cool down the return air from the pool and condense out the moisture within the space. The pool room temperatures require that the room be held at 82 degrees or more to maintain a lower evaporation rate across the pool surface. In order to get the temperature of the air up to 82 degrees a heating or reheat style post heating coil is required to be running all of the time. If the DX compressor system has hot gas reheat to achieve this function the compressor needs to run 100% of the time to produce this reheat. A refrigerant pool dehumidification system uses very expensive electricity to heat the air in lieu of less expensive natural gas or Cogeneration concepts to heat the air and water in the pool room environment.

For example, let’s look at a 30×16 hotel pool requiring a 1,500 CFM refrigerant dehumidifier that would require 43,000 BTUH of capacity via the on board DX compressor and outdoor condenser hot air rejecter. The DX designed system would normally consume up to 3.8 kilowatts of electricity to dehumidify the pool room. The DX unit would remove up to 18 lbs. of moisture per hour as long as the pool room space temperature were maintained at 82 degrees at 60% relative humidity. However, the unit could only handle up to 700 CFM of outdoor air into the pool space. If larger amount of outside air were introduced into the unit the 18 lbs. per hour would be reduced. At $.10 per KWH energy costs for this DX system running 24 hours a day, 7 days a week all year long would cost the owner $3,328 per year to operate. In order to control energy costs this style of system only introduces 700 CFM of outside air, thus indoor air quality is poor and chloramine levels are high.

A typical pool room environment at 82 degrees, 60% relative humidity that has a moisture content of 98.43 grains of moisture per pound of air is a design standard. When using the NU-1500 the small pool described above would maintain the discharge air grain level at 98.44 grains per pound even when outside air reached 95 degrees dry bulb/75 degrees wet bulb. The NU-1500 would only require 1.2 kilowatts electrical energy to meet the design criteria and would be using 1,500 CFM of clean oxidized air. The operating cost of the NU-1500 would be $1,051 per year, at $.10 per KWH to operate. The temperature of the supply air in the winter based on a 10 degree day would be 76 degrees, therefore only a 10 degree rise of BTUH would be required to maintain the 82 degree air temperature of the space.

A small boiler loop can be utilized at 160-180 degrees at 16,200 BTUH. The cost to run the heat is only $.16 per hour when the cost of natural gas is $1 per 100,000 BTUH or $3.84 per day to operate. A typical winter month has a heating cost for the NU-1500 incoming outside air of $92.16 per month. The Nu-1500 runs 50% more efficiently and maintains a healthier environment than the DX refrigerant system at like airflows and capacities.

Why is the NU-1500 better?

Highly competitive on first cost
Significantly reduced operating and energy cost
The outside Air is exchanged by utilizing a special counter flow polymer energy exchanger, with no moving parts.
Polymer Micro-tube exchanger has 91% thermal efficiency and 34% latent efficiency and requires no maintenance.
Each counter flow exchanger contains 960 square feet of surface area for supply air to come in contact with high temperature pool exhaust air.
Totally sealed and fabricated with high-grade industrial polymer plastic with no chemical additives.
Exchanger will not rust or degrade over time.
Exchanger performance certified by ETL.
Field erected on-site.
All components fit through a standard 36″ door.
Highly efficient supply and exhaust blowers designed to operate at the lowest possible KWH rate.
Blowers operate with a micro drive inverter controller.
Micro drive receives input control signal from a duct mounted return air temperature and humidity sensor.
Micro drives maintain proper airflow speeds to guarantee a negative pressure in the pool area at all times.


NU-1500 Components

HRV Stand:

The all-aluminum HRV stand is designed to support the HRV Exchanger in a vertical position. Each wall panel is designed with a 5 layer thermal break design with a foam core. The outside of the foam core panel is all aluminum with a white polyester finish. The foam core panel is attached with industrial strength adhesive using stainless steel fasteners. Each panel is 1″ thick. Four support legs lift the stand 6″ off the ground for connection to drains.


A typical indoor pool requires both temperature control (between 75 and 85 degrees) and humidity control (between 50% and 60% relative humidity). The NU-1500 temperature and humidity control system is designed to create an outdoor environment in your indoor pool. Includes simple LED viewer. 24 volt powered.

(Factory supplied when the optional hot water heating coil is selected)
The wall mounted temperature set point controller will advise the hot water 3-way heating valve and the on-board heating coil to operate the temperature set point of the room air at a setting of 2 degrees above the pool water temperature. Controller can be mounted in the pool space or mechanical room on an interior wall. Room temperature can be manually increased or decreased thru the LED screen interface.
Controller must be field wired from wall location to duct transmitter location.

The humidity point is factory set at 60% RH. The duct mounted humidity transmitter located in the unit’s return air, monitors the temperature and relative humidity. It sends a 0-10 volt signal, based on the humidity range, to the wall mounted VFD fan drive. Ribbon cable connects to temperature control. Uses replaceable 3% humidity duct sen-sors. Controller must be field wired using a 24 VAC input.

MERV-8 Outside Air Filter:

A special washable outside air filter assembly cleans the incoming outside air before it enters the HRV exchanger. This uniquely designed filter contains four (4) stages of cleaning all in one frame. It is contained within an all-aluminum extrusion box frame with a slide out filter sub frame. The NU-1500 has a side access door for easy access to the filter.
Washable filter comes with a 10 year warranty.
Filter is designed for easy soap and water cleaning.
Contractor installs the filter between the outside air connection in the building and the inlet connection on the supply air blower.

BI-15 Airfoil Blowers:

Supply and exhaust airfoil blowers are designed with the latest state of the art wheel. Each blower is comprised of a 16 gauge all welded housing and a backward incline all welded wheel. Both housing and wheels are coated with Heresite to protect the fans from rust and corrosion.
1 HP high efficient ODP motors running on 230 volts/3 phase.
Motors draw .8 amps at full operation.
Noise is contained in housing and is under 65 DB.
Tested and certified for air performance by AMCA. Antivibration mats supplied with each fan.
Fan weight = 200 lbs. each

VFD Fan Micro Drives:

Each airfoil blower is supplied with a VFD fan micro drive inverter. Each drive contains a PID loop control and allows the supply blower speed and flow to be 10% less than the pool exhaust blower airflow. This offset maintains the pool room at a negative pressure at all times.
Converts 120 volt AC input power to 230 volt/3 phase fan control power.
Has a LED screen for visual access to set points and values.

Anti-vibration Mats:

Each airfoil blower is supplied with a special rubber anti vibration mat with caution strips. The caution strips warn operators that they are approaching rotating machinery.

Micro Channel HRV Heat Exchanger:

All polymer construction
Over 900 square feet of surface for exchange
Low pressure drop
Fused & welded polymer case
Will not rust or corrode
20 year warranty
Air flow range = 900 to 1,600 CFM
Requires less heat
87% thermal effectiveness
Pressure drop .20 to .35
34% latent recovery
Weighs only 280 lbs.
Self-cleaning micro tube design
Air speed designs are under 1.56 FPM
Media speed at 1,500 CFM airflow

Complete Component Listing:

(1) NU-1500 HRV exchanger
(1) 48″ x 25″ x 31″ HRV stand
(1) Air filter box with filter
(2) BI-15 Airfoil blowers
(2) 1HP 230v/3ph/60Hz VFD fan micro drives/Nema 1 casing
(2) Anti vibration mats
(1) Wiring diagrams
(1) Service manual


(1) Wall mounted temperature controller
(1) Wall mounted humidity controller
(2) Wall plates
(1) 120/24 Control transformer
(1) Humidity duct sensor
(1) Duct insertion support
(1) Power transformer

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