• TABLE OF CONTENTS
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 Copyright
 Introduction
 Components of aquaculture...
 Energy saved in pumping
 Selection of pumps and plumbing...
 Heating systems
 Housing
 Conclusions






Title: Energy use of recycling water aquaculture systems for ornamental fish production
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00049207/00001
 Material Information
Title: Energy use of recycling water aquaculture systems for ornamental fish production
Series Title: Circular
Physical Description: 5 p. : ill. ; 28 cm.
Language: English
Creator: Bucklin, R. A
Florida Cooperative Extension Service
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville
Publication Date: 1993
 Subjects
Subject: Fish-culture -- Water-supply -- Recycling -- Florida   ( lcsh )
Fish-culture -- Energy consumption -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: R.A. Bucklin ... et al..
General Note: Caption title.
General Note: "May 1993."
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00049207
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: oclc - 28532744

Table of Contents
    Copyright
        Copyright
    Introduction
        Page 1
    Components of aquaculture systems
        Page 2
    Energy saved in pumping
        Page 2
        Page 3
    Selection of pumps and plumbing components
        Page 4
    Heating systems
        Page 4
    Housing
        Page 5
    Conclusions
        Page 5
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida




lot

/O1
/^ UNIVERSITY OF

SFLORIDA

Florida Cooperative Extension Service


Circular 1095
May 1993


Energy Use of Recycling Water Aquaculture Systems for
Ornamental Fish Production1
R. A. Bucklin, C. D. Baird, C. A. Watson and F. A. Chapman2


INTRODUCTION

Most of Florida's ornamental fish production
takes place in outdoor ponds, where production
success is often subject to such natural occurrences as
winter weather, the presence of aquatic weeds, and
predation by birds and other animals. Most facilities
also use tanks for holding, breeding, and producing
certain fish species. Energy consumption is greatest
for water pumping and heating and can become a
major business expense, especially during the winter
and spring.

Increased water consumption is also becoming a
critical problem in Florida, as more and more people
compete for the same resource. Pond production
requires not only available water but also land
suitable for fish pond development. Land values and
regulations controlling development continue to
eliminate many potential pond production sites, a
situation that threatens to limit expansion of the
ornamental fish production industry in Florida.

One alternative is a recirculating aquaculture
system, which removes some of the inefficiencies
inherent in production or holding systems. Water
reuse reduces pumping costs and retains energy
normally used to heat water. In addition, it enables
production to occur in a controlled environment
where losses to predators and seasonal drought do


not influence production plans. Finally, it permits a
reduction in water consumption and the production of
large numbers of fish in a small area.

This publication describes the components of a
recirculating water system that can be used for
holding and/or production of ornamental fish. It also
explains how such a system can be designed to be
more energy efficient than conventional systems.
Recirculating systems may not be applicable to all
situations, since they require a high level of
management capability and a large initial capital
investment. Certain species and varieties of
ornamental fish may not reproduce or develop in an
indoor system, and water quality and disease
management have historically caused problems in
recirculating systems. The alternative offered in this
publication can save energy and reduce water
consumption in many situations, especially in holding
facilities. This is not to suggest that pond production
of ornamental fish is not a viable option. Information
regarding the energy required for conventional
ornamental fish production, especially in open ponds,
is extremely limited. Also, since production
techniques vary within the industry, it is difficult to
generalize about energy requirements. Nevertheless,
the data and examples provided in this publication
will serve to demonstrate how modern technologies
can be employed to reduce the costs of ornamental
fish production.


1. This document was published May 1993 as Circular 1095, a series of the Florida Energy Extension Service, Florida Cooperative Extension
Service, Institute of Food and Agricultural Sciences, University of Florida.
2. RA. Bucklin, Associate Professor, and C.D. Baird, Professor, Agricultural Engineering; CA. Watson, Aquaculture Extension Agent II,
Hillsborough County, Seffner; and F.A. Chapman, Assistant Professor of Fisheries and Aquaculture, Cooperative Extension Service,
Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611.
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research,
educational information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap,
or national origin. For information on obtaining other extension publications, contact your county Cooperative Extension Service office.
Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences / University of Florida / John T. Woeste, Dean


UNtiVERSITY OF FL-('-.lA LIMAKIE-[






:-r; nlj o -r:'i:ling Water Aquaculture Systems


F 3G0
F6I c


COMPONENTS OF
AQUACULTURE SYSTEMS


The basic components of a typical outdoor pond
SCIi: systemem are a water supply, a water distribution system,
L i, A.'., an aeration system, fish ponds, and a water discharge
or retention system. Many ponds are equipped with
covers to provide protection from cold and predators.
Most buildings used for holding orfish production are
heated. Some facilities directly heat the water in
these buildings, employing conventional gas or electric
resistance heaters.

Although recycling systems may vary in several
respects, a typical system consists of a water supply, a
water distribution system, tanks for holding fish, a
filtration system, an aeration/degasser system, a
heating/cooling system, and a building to house the
system (see Figure 1).

ENERGY SAVED IN PUMPING

Most of the energy used in ornamental fish
production is applied to pumping and temperature
control. This publication highlights these two
important aspects of ornamental fish production
systems.

While flow rates in a recirculating water system
may actually be higher than in flow-through systems,
the lower pumping head saves energy. In flow-
through systems, water is pumped from wells as deep
as 500 feet. Many wells on fish farms have diameters
of 4-6 inches, and pumps often have 5- to 10-
horsepower capacities. Recirculating systems, on the
other hand, may pump as little as 10 feet of head and
can be operated on as little as 1/2 horsepower. In a
recycling system, the only head losses are elevation
head losses between the tanks on the floor and
elevated tanks and friction head losses in the pipes,
fittings, and filter.

Electric energy is sold by the kilowatt hour (1
horsepower = 0.746 kilowatts). In Florida in 1992, a
typical price for a kilowatt hour of electricity was
$0.08. Operating a 5- to 10-horsepower pump at 75%
efficiency costs approximately $10-$19 per day, while
operating a 1/2-horsepower pump costs about $1 per
day. Clearly, the lower initial and operating costs of
the smaller pump are among the major advantages of
recycling systems.

Before pumps are selected for a recycling water
system, the required flow rate must be determined.


Page 2


This is based on the flow rate needed to maintain
water quality for a given weight of fish and the
expected head requirements of the system. The main
limiting factors in recycling systems are nitrogenous
wastes (e.g., ammonia, nitrites, and nitrates) and
oxygen. There must be sufficient flow through the
tanks to replace water before it becomes high in
nitrogenous wastes or low in dissolved oxygen.
Nitrogenous wastes, produced in proportion to the
amount of feed consumed by the fish in the system,
almost always constitute the primary limiting factor.
Most of the energy that provides flow in a recycling
system is used to overcome differences in elevation
between the sump and the fish tanks and to overcome
friction in the plumbing. The energy that provides
flow in outdoor flow-through systems is consumed
chiefly in pumping water from a source such as a
deep well and in overcoming friction in the pipes and
fittings of the water distribution system. Energy is
also used initially to fill both indoor water recycling
systems and outdoor ponds. When viewed as a
proportion of the total energy used per unit of
production, the amount of energy used for filling
water recycling systems is small; however, the energy
used to fill outdoor ponds contributes significantly to
production costs in some systems.

The values in Table 1 are based on the following
assumptions:

* The fish consume an amount of feed equivalent
to 1% of their total body weight every day.

The feed has a protein content of 35%.

The biological filter has a removal efficiency of
35%.

All the ammonia produced by the metabolizing of
feed is excreted in 6 hours.

The fish are fed four times per day.

For the water recycling systems described in Table
1, a flow rate of 0.038 gpm per pound of fish is
required to control ammonia. In an average water
recycling system housed in a 20- by 30-foot structure,
with 550 pounds of fish and a flow rate of 21 gpm,
approximately 50 feet of 1-1/2-inch PVC pipe with a
friction head loss of 1.6 feet would be required.
Assuming there were twelve 90* elbows and four gate
valves in the system, an additional 1.6 feet of water
head loss would occur in the elbows and gate valves.
A typical elevation head for a system of this size is 5






:-r; nlj o -r:'i:ling Water Aquaculture Systems


F 3G0
F6I c


COMPONENTS OF
AQUACULTURE SYSTEMS


The basic components of a typical outdoor pond
SCIi: systemem are a water supply, a water distribution system,
L i, A.'., an aeration system, fish ponds, and a water discharge
or retention system. Many ponds are equipped with
covers to provide protection from cold and predators.
Most buildings used for holding orfish production are
heated. Some facilities directly heat the water in
these buildings, employing conventional gas or electric
resistance heaters.

Although recycling systems may vary in several
respects, a typical system consists of a water supply, a
water distribution system, tanks for holding fish, a
filtration system, an aeration/degasser system, a
heating/cooling system, and a building to house the
system (see Figure 1).

ENERGY SAVED IN PUMPING

Most of the energy used in ornamental fish
production is applied to pumping and temperature
control. This publication highlights these two
important aspects of ornamental fish production
systems.

While flow rates in a recirculating water system
may actually be higher than in flow-through systems,
the lower pumping head saves energy. In flow-
through systems, water is pumped from wells as deep
as 500 feet. Many wells on fish farms have diameters
of 4-6 inches, and pumps often have 5- to 10-
horsepower capacities. Recirculating systems, on the
other hand, may pump as little as 10 feet of head and
can be operated on as little as 1/2 horsepower. In a
recycling system, the only head losses are elevation
head losses between the tanks on the floor and
elevated tanks and friction head losses in the pipes,
fittings, and filter.

Electric energy is sold by the kilowatt hour (1
horsepower = 0.746 kilowatts). In Florida in 1992, a
typical price for a kilowatt hour of electricity was
$0.08. Operating a 5- to 10-horsepower pump at 75%
efficiency costs approximately $10-$19 per day, while
operating a 1/2-horsepower pump costs about $1 per
day. Clearly, the lower initial and operating costs of
the smaller pump are among the major advantages of
recycling systems.

Before pumps are selected for a recycling water
system, the required flow rate must be determined.


Page 2


This is based on the flow rate needed to maintain
water quality for a given weight of fish and the
expected head requirements of the system. The main
limiting factors in recycling systems are nitrogenous
wastes (e.g., ammonia, nitrites, and nitrates) and
oxygen. There must be sufficient flow through the
tanks to replace water before it becomes high in
nitrogenous wastes or low in dissolved oxygen.
Nitrogenous wastes, produced in proportion to the
amount of feed consumed by the fish in the system,
almost always constitute the primary limiting factor.
Most of the energy that provides flow in a recycling
system is used to overcome differences in elevation
between the sump and the fish tanks and to overcome
friction in the plumbing. The energy that provides
flow in outdoor flow-through systems is consumed
chiefly in pumping water from a source such as a
deep well and in overcoming friction in the pipes and
fittings of the water distribution system. Energy is
also used initially to fill both indoor water recycling
systems and outdoor ponds. When viewed as a
proportion of the total energy used per unit of
production, the amount of energy used for filling
water recycling systems is small; however, the energy
used to fill outdoor ponds contributes significantly to
production costs in some systems.

The values in Table 1 are based on the following
assumptions:

* The fish consume an amount of feed equivalent
to 1% of their total body weight every day.

The feed has a protein content of 35%.

The biological filter has a removal efficiency of
35%.

All the ammonia produced by the metabolizing of
feed is excreted in 6 hours.

The fish are fed four times per day.

For the water recycling systems described in Table
1, a flow rate of 0.038 gpm per pound of fish is
required to control ammonia. In an average water
recycling system housed in a 20- by 30-foot structure,
with 550 pounds of fish and a flow rate of 21 gpm,
approximately 50 feet of 1-1/2-inch PVC pipe with a
friction head loss of 1.6 feet would be required.
Assuming there were twelve 90* elbows and four gate
valves in the system, an additional 1.6 feet of water
head loss would occur in the elbows and gate valves.
A typical elevation head for a system of this size is 5






Energy Use of Recycling Water Aquaculture Systems

feet. Therefore, the total head in
plumbing would be 8.2 feet of water.
Assuming an additional 5.8 feet of Makeup
head loss in filters, the total head Water
would be 14.0 feet of water. If a
pump with an operating efficiency of
50% were used, a 0.15-horsepower
(i.e., 0.11-kilowatt) motor would be
required to produce a flow of 21 gpm
against 14 feet of water head. A
motor operated continuously at an
efficiency of 75% would require 3.5
kilowatt hours of energy per day.
Aeratiorn
Oxygenatfor
A flow-through system housed in ygnat
a similar structure and using tanks of
the same size would require a
continuous flow of 21 gpm from a
deep well. A standard ornamental
fish production system includes a 150-
foot well located 50 feet from the gure Typ
building. This type of system requires
a pump that can supply the same quantity of water as
the recycling system but at a much higher head. The
head losses for the system include 150 feet of
elevation head loss from the water level to the ground
surface and a friction loss of 1.6 feet of water in the
50 feet of pipe between the well and the production
structure, in addition to friction losses in the
plumbing within the structure. A typical flow-through
system with 550 pounds of fish and a flow of 21 gpm,
housed in a 20- by 30-foot structure, would require
approximately 25 feet of 1-1/2-inch PVC pipe, with a
friction loss in the pipe of 0.8 feet of water.
Assuming there were six 90* elbows and two gate
valves in the system, an additional 1.6 feet of water
head loss would occur in the elbows and gate valves.
A typical elevation head for tanks in a system of this
size is 5 feet. The total dynamic head for the flow-
through system would be 158.2 feet of water. A
pump operating at an efficiency of 50% would require
1.7 horsepower (i.e., 1.25 kilowatts) to produce a flow
of 21 gpm against 158.2 feet of water head. If the
pump were powered by an electric motor operated
continuously at 75% efficiency, it would use 40.1
kilowatt hours of energy per day.

In a typical 550-pound system, 36.6 fewer kilowatt
hours of energy per day are consumed by using
recycling instead of flow-through systems. The
ornamental fish industry in Florida is composed of
1,240 acres of outdoor ponds with an annual
production of approximately 2,280,000 pounds of fish.


Page 3


aal water recycling aquaculture production system.

If half the industry used indoor water recycling
production systems similar to the one described, the
energy savings would be 76,000 kilowatt hours per
day, or 27,700,000 kilowatt hours per year. At $0.08
per kilowatt hour, this would result in savings of
$6,000 per day, or $2,200,000 per year for the
industry.

It is difficult to make comparisons between
indoor recycling systems and outdoor pond systems
because of system variations. In general, however,
recycling systems have the potential to reduce
pumping costs, particularly during spring droughts
when water levels must be maintained, and during
cold periods when water is pumped to maintain water
temperatures. Energy usage for outdoor ponds varies
considerably and is heavily influenced by the depth of
water in a system's well. When well water is available
at a depth of 70 feet or less, or when groundwater is
high and evaporation low, the difference between the
amount of energy consumed in recycling systems and
that used in pond systems is minimal. However,
recycling systems have potential advantages over pond
systems when well water is available only at a depth
greater than 70 feet or when space is limited.
Assuming an average weight of 1 gram per fish and a
volume of 10,000 fish per pond, a 550-pound recycling
system would have the same capacity as 24 outdoor
ponds. In addition, a typical 24-pond system occupies
2-3 acres of land that could be used more productively
for other purposes.






Energy Use of Recycling Water Aquaculture Systems

Table 1. Flow rates for typical water recycling systems.

Weight of Weight of Flow rate Flow rate
fish In fish In In liters gallons
kilograms pounds per hour per
minute
2,000 4,400 38,400 169
1,000 2,200 -19,200 -85
500 1,100 9,600 42
250 550 4,800 21


SELECTION OF PUMPS AND
PLUMBING COMPONENTS

Size and output must be considered when
selecting pumps. A pump must be large enough to
deliver the desired quantity of water, usually
measured in liters per hour or in gallons per minute.
The pump must also be able to deliver this quantity
of water at the operating pressure or total head
required by the system.

Total head includes the pressure required at the
pipe outlet (i.e., pressure head); the pressure needed
to raise water to the desired elevation (elevation
head); the pressure necessary to overcome friction
(friction head); and the pressure required to raise
water from a sump or other water source to the pump
(suction head). Head can be measured either in feet
of water or in pounds per square inch (psi) (psi x 2.31
= feet of water).

A pump's efficiency varies with the rate of output
and the total dynamic head. The manufacturer should
provide a table or graph describing the relationship
between these factors and pump efficiency. The
consumer must make sure that the pump selected
offers the desired output at the highest pump
efficiency. Careful pump selection enables the user
to operate a smaller pump (i.e., one with a lower
horsepower) than is required by most wells.

PVC pipe and fittings are recommended for
recycling water systems. The advantages of PVC pipe
are that it is relatively inexpensive and is subject to
less pressure drop due to friction than other types of
pipe. Fittings are a major source of friction loss in
piping systems. A 90* standard elbow experiences the
same amount of pressure drop as 32 diameters of
straight pipe. Therefore, when the layout of a pipe
system is being planned, the number of elbows and


Page 4


other fittings should be minimized. Since valves are
another source of friction loss, gate valves should
always be used instead of globe valves. An open gate
valve has a friction loss equivalent to 7 diameters of
straight pipe, whereas an open globe valve has a
friction loss equivalent to 300 diameters of straight
pipe.

HEATING SYSTEMS

Heating systems in conventional fish production
buildings are often inefficient because they typically
heat air rather than water. When water is heated,
either gas or electric water heaters are employed,
limiting efficiency. In addition, many of these
buildings use flow-through systems, which allow
heated water to be discharged and wasted. In
outdoor pond systems, plastic covers must be used or
water pumped to protect the fish during severe winter
weather. Using conventional methods often slows or
stops production during periods of peak market value.

Water heating is costly and requires a great deal
of energy. In flow-through systems, most of this
energy is lost when the water is discharged. Recycling
water systems save a significant amount of energy and
can provide year-round production capabilities. A
recycling system directly heats water; then, instead of
discarding this expensive heated water, the recycling
system removes the nitrogenous wastes, aerates and
degasses the water, and returns the water to the
tanks.

Most indoor systems rely on electric resistance
heaters to heat water. Although these heaters are
clean, convenient to use, and accessible, they are
expensive to operate. For operations requiring heat
for more than a few days per year, a heating system
that burns fuel to heat water is much less costly to
operate than one employing electric resistance
heaters. For example, assuming a cost of $1 per
gallon, propane burned to generate heat provides
about 80,000 Btu of energy per dollar. In
comparison, if electricity costs $0.08 per kilowatt-
hour, the amount of electricity used to power
resistance heating elements provides only 43,000 Btu
per dollar.

Heat pumps offer another alternative for water
heating. They allow temperature to be controlled at
lower costs than either conventional electric or gas-
powered heaters and have the additional advantage of
being able to cool water during the summer. For
specific information on selecting and installing a heat






Energy Use of Recycling Water Aquaculture Systems

Table 1. Flow rates for typical water recycling systems.

Weight of Weight of Flow rate Flow rate
fish In fish In In liters gallons
kilograms pounds per hour per
minute
2,000 4,400 38,400 169
1,000 2,200 -19,200 -85
500 1,100 9,600 42
250 550 4,800 21


SELECTION OF PUMPS AND
PLUMBING COMPONENTS

Size and output must be considered when
selecting pumps. A pump must be large enough to
deliver the desired quantity of water, usually
measured in liters per hour or in gallons per minute.
The pump must also be able to deliver this quantity
of water at the operating pressure or total head
required by the system.

Total head includes the pressure required at the
pipe outlet (i.e., pressure head); the pressure needed
to raise water to the desired elevation (elevation
head); the pressure necessary to overcome friction
(friction head); and the pressure required to raise
water from a sump or other water source to the pump
(suction head). Head can be measured either in feet
of water or in pounds per square inch (psi) (psi x 2.31
= feet of water).

A pump's efficiency varies with the rate of output
and the total dynamic head. The manufacturer should
provide a table or graph describing the relationship
between these factors and pump efficiency. The
consumer must make sure that the pump selected
offers the desired output at the highest pump
efficiency. Careful pump selection enables the user
to operate a smaller pump (i.e., one with a lower
horsepower) than is required by most wells.

PVC pipe and fittings are recommended for
recycling water systems. The advantages of PVC pipe
are that it is relatively inexpensive and is subject to
less pressure drop due to friction than other types of
pipe. Fittings are a major source of friction loss in
piping systems. A 90* standard elbow experiences the
same amount of pressure drop as 32 diameters of
straight pipe. Therefore, when the layout of a pipe
system is being planned, the number of elbows and


Page 4


other fittings should be minimized. Since valves are
another source of friction loss, gate valves should
always be used instead of globe valves. An open gate
valve has a friction loss equivalent to 7 diameters of
straight pipe, whereas an open globe valve has a
friction loss equivalent to 300 diameters of straight
pipe.

HEATING SYSTEMS

Heating systems in conventional fish production
buildings are often inefficient because they typically
heat air rather than water. When water is heated,
either gas or electric water heaters are employed,
limiting efficiency. In addition, many of these
buildings use flow-through systems, which allow
heated water to be discharged and wasted. In
outdoor pond systems, plastic covers must be used or
water pumped to protect the fish during severe winter
weather. Using conventional methods often slows or
stops production during periods of peak market value.

Water heating is costly and requires a great deal
of energy. In flow-through systems, most of this
energy is lost when the water is discharged. Recycling
water systems save a significant amount of energy and
can provide year-round production capabilities. A
recycling system directly heats water; then, instead of
discarding this expensive heated water, the recycling
system removes the nitrogenous wastes, aerates and
degasses the water, and returns the water to the
tanks.

Most indoor systems rely on electric resistance
heaters to heat water. Although these heaters are
clean, convenient to use, and accessible, they are
expensive to operate. For operations requiring heat
for more than a few days per year, a heating system
that burns fuel to heat water is much less costly to
operate than one employing electric resistance
heaters. For example, assuming a cost of $1 per
gallon, propane burned to generate heat provides
about 80,000 Btu of energy per dollar. In
comparison, if electricity costs $0.08 per kilowatt-
hour, the amount of electricity used to power
resistance heating elements provides only 43,000 Btu
per dollar.

Heat pumps offer another alternative for water
heating. They allow temperature to be controlled at
lower costs than either conventional electric or gas-
powered heaters and have the additional advantage of
being able to cool water during the summer. For
specific information on selecting and installing a heat






Energy Use of Recycling Water Aquaculture Systems

pump in a recycling system, University of Florida
IFAS Circular 1096, Heat Pump for Heating and
Cooling Water for Aquacultural Production, should be
consulted.

HOUSING

A water recycling system must be housed in a
building to be effective. A wide array of structures
can be used for ornamental fish production.
Greenhouse structures such as those used by the
horticulture industry for plant production are
commonly employed. Greenhouse structures are
inexpensive, with material costs of approximately $1
per square foot; however, they have short lifespans,
are very hot in the summer, and are difficult to
insulate properly, causing high energy usage for
heating systems in the winter and cooling systems in
the summer. Economical wood or metal frame
structures, with material costs as low as $4-$6 per
square foot, offer an alternative to greenhouse
structures. Although construction costs for wood or
metal frame buildings are greater than for greenhouse
structures, making their initial cost higher, these
structures have much longer lifespans than
greenhouse structures. The best greenhouse plastics
last for only three years in Florida, while a well-
constructed wood or metal frame building has an
expected lifespan of more than 20 years. Wood or
metal frame buildings are also better able to
withstand the high winds that occur periodically in
Florida.

A wood or metal frame structure can easily be
insulated, reducing its energy usage to a level well
below that of a greenhouse structure. The overall
thermal resistance to heat flow, referred to as the
"total R," indicates the effectiveness of a building's
insulation. The higher the total R value, the lower
the heat loss or gain. A double poly greenhouse has
a total R value of 1.4 hr-ft2o*F/Btu. A frame
structure with a total R value of 10-20 hr-ft2.oF/Btu
can easily be constructed. Structures with higher total
R values reduce heat loss in the winter and heat gain
in the summer, lowering energy consumption.

CONCLUSIONS

Indoor recycling systems offer several advantages
over conventional ornamental fish production and
holding facilities, including increased energy
efficiency. The use of such modern system
components as heat pumps and energy-efficient
building materials allows producers to minimize


Page 5


energy expenditures. Because recycling systems have
lower water head requirements than outdoor pond
systems, equal or greater flow rates can be achieved
with less energy. Proper design, including accurate
calculation of head requirements, minimization of the
number of fittings and valves used in plumbing
systems, and careful pump selection diminish energy
needs. Additional benefits of using recycling systems
may include reductions in water consumption per unit
of fish produced, decreases in land usage, elimination
of losses due to predation, and attainment of
year-round production capabilities.

Recycling systems will not immediately replace
pond-based production facilities in Florida. Problems
characteristic of certain species, fish diseases, water
quality management issues, and economic factors will
continue to favor the use of outdoor ponds for some
time to come. Nevertheless, recycling systems offer
real solutions to many problems encountered in
commercial ornamental fish production. Foremost
among these solutions is a substantial decrease in
energy usage.






Energy Use of Recycling Water Aquaculture Systems

pump in a recycling system, University of Florida
IFAS Circular 1096, Heat Pump for Heating and
Cooling Water for Aquacultural Production, should be
consulted.

HOUSING

A water recycling system must be housed in a
building to be effective. A wide array of structures
can be used for ornamental fish production.
Greenhouse structures such as those used by the
horticulture industry for plant production are
commonly employed. Greenhouse structures are
inexpensive, with material costs of approximately $1
per square foot; however, they have short lifespans,
are very hot in the summer, and are difficult to
insulate properly, causing high energy usage for
heating systems in the winter and cooling systems in
the summer. Economical wood or metal frame
structures, with material costs as low as $4-$6 per
square foot, offer an alternative to greenhouse
structures. Although construction costs for wood or
metal frame buildings are greater than for greenhouse
structures, making their initial cost higher, these
structures have much longer lifespans than
greenhouse structures. The best greenhouse plastics
last for only three years in Florida, while a well-
constructed wood or metal frame building has an
expected lifespan of more than 20 years. Wood or
metal frame buildings are also better able to
withstand the high winds that occur periodically in
Florida.

A wood or metal frame structure can easily be
insulated, reducing its energy usage to a level well
below that of a greenhouse structure. The overall
thermal resistance to heat flow, referred to as the
"total R," indicates the effectiveness of a building's
insulation. The higher the total R value, the lower
the heat loss or gain. A double poly greenhouse has
a total R value of 1.4 hr-ft2o*F/Btu. A frame
structure with a total R value of 10-20 hr-ft2.oF/Btu
can easily be constructed. Structures with higher total
R values reduce heat loss in the winter and heat gain
in the summer, lowering energy consumption.

CONCLUSIONS

Indoor recycling systems offer several advantages
over conventional ornamental fish production and
holding facilities, including increased energy
efficiency. The use of such modern system
components as heat pumps and energy-efficient
building materials allows producers to minimize


Page 5


energy expenditures. Because recycling systems have
lower water head requirements than outdoor pond
systems, equal or greater flow rates can be achieved
with less energy. Proper design, including accurate
calculation of head requirements, minimization of the
number of fittings and valves used in plumbing
systems, and careful pump selection diminish energy
needs. Additional benefits of using recycling systems
may include reductions in water consumption per unit
of fish produced, decreases in land usage, elimination
of losses due to predation, and attainment of
year-round production capabilities.

Recycling systems will not immediately replace
pond-based production facilities in Florida. Problems
characteristic of certain species, fish diseases, water
quality management issues, and economic factors will
continue to favor the use of outdoor ponds for some
time to come. Nevertheless, recycling systems offer
real solutions to many problems encountered in
commercial ornamental fish production. Foremost
among these solutions is a substantial decrease in
energy usage.




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