American Aldes LT-15, LT-20 specifications Ducting Considerations, General Features

HRV LT-15, LT-20

HEAT RECOVERY VENTILATOR

PRODUCT

SPECIFICATIONS

AND ENGINEERING

INFORMATION

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SUBMITTAL DATA

		746-7-00
ALDES Model HRV LT-15 and LT-20 are	ALDES HRV LT-15, LT-20
exhaust stale indoor air and supply fresh air
compact heat recovery ventilators designed to
from outdoors. When operated at full speed,	Air to Air Heat Recovery Ventilator
the LT-15 unit can meet the general ventilation
requirements (0.35 air changes per hour—
ASHRAE 62-1989) of a home up to 2800 sq. ft,
and the LT-20 of a home up to 4000 sq. ft. (On
a smaller home, they can be operated at lower
speed, reserving excess capacity for tempo-
rary increases in humidity or other contami-
nants.) They are technically advanced con-
trolled mechanical ventilation systems designed
to meet the requirements of modern, tightly
built and highly insulated homes. They provide
a consistent supply of fresh air while lowering
heating costs during the winter by transferring
heat from the exhaust air to the fresh air stream.
During the summer they also reduce the load
on the air conditioner by lowering the tempera-
ture of the fresh outdoor air. (For southern
climates, where air conditioning costs are the		LT-15 PART NO. 28 045
major concern, one of the ERV models should
be considered, because of their ability to re-		LT-20 PART NO. 28 047
duce the humidity of the fresh air as well as
lowering the temperature.) The systems pro-	Disadvantages: Higher installed cost for addi-	Disadvantages: Higher operating costs when
vide an economical solution for excessive in-
	tional ductwork. Unless bedrooms are provided	air handler is required to distribute fresh air.
door humidity, odors, stuffiness, and other in-
	with some form of zoned heat, cooler supply air	Greater potential for draft with high air volumes
door air pollutants.
	to bedrooms may result in cooler temperature in	circulating at room temperature.
As the two air streams pass through the HRV,
	these spaces.
they are separated by thin plates of aluminum		FULLY INTEGRATED WITH FORCED AIR
in the core. The air streams do not mix, so there	HALF-DUCTED SYSTEM	The exhaust air is drawn from the return duct
is no recontamination of the fresh air by stale		and fresh air is supplied downstream in the
	Similar to fully ducted system, except supply air
air. Heat passes through the thermally conduc-		return duct or in the forced air heating supply
	delivered to a central location or to the return of
tive aluminum from the warmer air stream to the		ducting.
	a forced air system.
colder air stream, recovering most of the en-		Advantages: Lowest installation costs, with mini-
	Advantages: Low installation costs, as ductwork
ergy otherwise lost to the outdoors.
		malductwork. Thoroughmixingoffreshairthrough-
	is reduced. Good tempering of outdoor air when
DUCTING CONSIDERATIONS		out dwelling. Good tempering of outdoor air.
	ducted to the return of the furnace or heat pump.
Equally important to providing fresh air supply	Good ventilation efficiency, as pollutants are	Disadvantages: Requires forced air handler to
and exhaust of stale air is the means of assuring	exhausted with minimal mixing in the occupied	run continuously with the ventilation system, or
internal distribution of fresh air throughout the	spaces. Quiet bathroom and kitchen exhaust as	internal short-circuiting of supply and exhaust will
occupied space(s) and exhaust of stale air from	compared to conventional fans for these areas.	occur in the ducting. Higher electrical operating
highly polluted areas. The designer/specifier	Reduces cost of equipment to ventilate these	costs since air handler is required to distribute
should select the means of internal distribution	areas. Reduced roof and wall penetrations for	fresh air. Greater potential for draft with high air
when the ventilation system is planned. Three	independent fans.	volumes circulating at room temperature.
popular methods are detailed below, with ad-
vantages and disadvantages for each type.	GENERAL FEATURES
FULLY DUCTED SYSTEM	Thermally conductive aluminum heat exchange core, cross-flow design, easily
Dedicated exhaust and supply ducting to all	removed for cleaning or service.
spaces that can be closed. Fresh air to bed-	Efficient multi-speed motor drives a centrifugal blower in each air stream. Quiet,
rooms, dens, office spaces, etc. Exhaust air
	high efficiency PSC motor. 120 V., 1.4 Amps
from zones that produce high levels of pollut-
	Washable filters on each air stream protect the core. Easy to access and clean.
ants, such as kitchen, bathrooms, laundry, util-
ity rooms with stored household chemicals, etc.	Automatic defrost system activates when outdoor temperature falls below
Advantages: Lowest operating costs, relying	25 °F (-4 °C). The defrost cycle is preset at the factory so that after 17 minutes of
	outdoor temperature below this set point, the motor driven damper closes the
only on the small low power blowers of the HRV,
	outdoor air connection, and opens the defrost port to draw warm indoor air across
instead of large central air handlers in furnaces
	the core. After 3 minutes of defrost operation, the damper reverses to restore fresh
or heat pumps. Improved ventilation efficiency,
	air supply and close the defrost port. The 17 minute normal ventilation and 3
as pollutants are exhausted with minimal mix-
	minute defrost cycle continue until outdoor air temperature rises above
ing in the occupied spaces and freshest air is
	25 °F (-4 °C). During the 3 minute defrost cycle, the HRV operates at high speed.
delivered to zones where occupants spend
	The cycle times are installer selectable to meet the needs of different climates and
large amount of time. Quiet bathroom and
	operating conditions.
kitchen exhaust as compared to conventional
	Casing is heavy gauge pre-painted steel to protect against corrosion, and minimize noise.
fans for these areas. Reduced cost of equip-
ment to ventilate these areas. Reduced roof	Installation accessories and controls make installation simple.
and wall penetrations for independent fans.