Development of a Solar FLUPSY for British Columbia

Final Report

Evening Cove Oysters Ltd.
AIMAP-2010-P26

Table of contents

Executive Summary
1.0 Introduction
Overview
2.0 Background
2.1 Overview of FLUPSY principles
2.2 Roger Williams University – “Solar alt-Flupsy”
2.3 New VIU next generation shellfish raft design
3.0 Project Objectives
4.0 Operations and Initial Observations

Executive Summary

Because of the high cost of algae production in modern hatcheries, it is extremely cost advantageous to develop production strategies to transfer seed at small sizes (2-3mm) from the hatchery and to grow seed in an extensive nursery systems referred to as a FLUPSY (Floating Upweller System). For several years, staff at the Centre for Shellfish Research (CSR) have been following the development of a small solar powered FLUPSY technology developed by engineering students and researchers at Rogers Williams University, Rhode Island.

In a previous CSR project, we responded to industry need to develop a new shellfish aquaculture raft design using current state-of-the-art materials and techniques. The resulting “open” design has created next generation high quality rafts for the BC shellfish farming industry. This current project is the marriage of this recently developed renewable energy FLUPSY and our next generation shellfish culture raft.  A solar powered FLUPSY is novel on the west coast and we believe it has significant potential for adoption by the BC shellfish culture industry for a variety of species.

Our project objectives were to produce:

• A “farm scale” extensive nursery system that will allow the commercialization of native species such as the native cockle and other shellfish species;
• Greater sustainability for the shellfish industry via integration of renewable energy sources, reduced environmental risk and operational costs;
• Further integration and usefulness of the new CSR next generation shellfish culture raft design;
• A FLUPSY design that will have greater social acceptance through lower profile, consistency with shellfish culture rafts, add quiet operations; and
• Provision of FLUPSY design to industry for further adaption and improvement.

The modifications to a standard FLUPSY system to allow renewable solar energy to power the FLUPSY include: the fabrication of a shaft-driven axial flow pump; replacement of the standard 110VAC or diesel motor with a 90VDC motor; installation of solar panels, battery storage system and charge controller and; modification of the raft to support the new components. The total cost of electric components at the time of purchase was below $11,000. Significantly, these costs are well within costs or less than a diesel powered generator.

Adaptation of the VIU Shellfish raft to support the FLUPSY unit was relatively simple. Four galvanized 4”x4” angle iron components (AIT Technologies) were constructed and these were bolted underneath the raft structural beams. Wherever possible, consumer items were modified to build FLUPSY components, i.e. garden storage box for battery storage and structural plastic garbage can for FLUPSY bins. Total materials costs including the raft components but not including labour was approximately $31,000.

Initial testing indicates that the raft is achieving all desired criteria for performance and outcomes. However, we will not be able to document a full performance analysis until the completion of at least one growing season.

1.0 Introduction

Overview

The hatchery based culture of bivalve shellfish consists of two critical phases: a larval component which takes place in the hatchery; and a post-larval nursery phase which bridges the gap between the hatchery and grow-out environments, providing the animals with an opportunity to adapt to the wild conditions in a nurtured environment. Because of the high cost of algae production in modern hatcheries, it is extremely cost advantageous to develop production strategies to transfer seed at small sizes (2-3mm) from the hatchery to a nursery system supplied with natural phytoplankton. Nursery systems offer cost effective strategies to grow small seed to larger size 6mm – 10mm before transfer into the production grow-out system. While hatchery culture techniques are generally well established, the nursery phase (both land and water based) represents significant opportunities for optimization through the adoption of technological advances.

In many locations the extensive nursery systems consist of FLUPSY, which consist of floating platforms with shellfish seed suspended on “upweller” screens in the marine environment, through which seawater containing naturally produced phytoplankton is pumped. In British Columbia, these FLUPSY’s are typically large, centralized and require inputs of electricity, usually from generators for pumping. For new native species development, this presents a variety of challenges which restrict development. For example:

• Large systems are capital intensive and typically geared towards mass production of one species typically oysters, and do not facilitate smaller volumes with different requirements;
• Centralized systems do not facilitate the commercialization of native species that are restricted to be maintained within their own zones due to disease and genetic concerns established by Fisheries and Oceans Canada;
• Electrical demands require that FLUPSY’s are plugged into shore power often unavailable in remote aquaculture development areas; and
• Use of generators presents high operational costs, social issues relating to noise and increased risk of environmental contamination from accidental fuel spills.

Additionally almost all FLUPSY’s are “one-offs” built typically by operators and little information exists to provide design guidance, compare construction details and efficiencies.
Without such information errors inevitably will be repeated.

For several years, the CSR team has been following emerging technological developments on the east coast of North America that potentially may greatly address shellfish nursery limitations including a small solar powered FLUPSY technology developed by engineering students and researchers at Rogers Williams University, Rhode Island,USA.

This technology is novel on the west coast and we believe it has significant potential for adoption by the BC shellfish culture industry for a variety of species.

2.0 Background

This project is the marriage of two recently developed advancements on FLUPSY and suspended shellfish culture raft technologies.

2.1 Overview of FLUPSY principles.

FLUPSY is essentially a field version of a standard shellfish hatchery upweller. Upwellers used for small shellfish seed consist of a cylinder or rectangular bin with a fine mesh screen on the bottom on which shellfish juveniles (typically clams oysters) are maintained. A flow of water (and phytoplankton feed) are induced to flow upwards through the screen and past the shellfish juveniles. At optimal flow the seed is maintained in what is called a “fluidized bed” in which the seed tumble and mix gently. This way the seed have uniform access to feed flowing past them.

In the FLUPSY, the upweller is taken out into the environment and floated on the surface of the ocean. By having little to no pumping head it is highly efficient to flow significant amounts of seawater and feed past the seed.

Commercial FLUPSYs typically consist of six or more “bins” that are on either side of a central channel. These bins may range between 0.25 to 1m2 surface area. Water is evacuated from the centre channel by means of a propeller or paddlewheel pump; this causes water to flow through the FLUPSY bins into the centre channel.

2.2 RogerWilliamsUniversity – “Solar alt-Flupsy”

First observed during a research visit by CSR staff in 2008, Dr. Dale Leavitt at Roger Williams University (RWU) in Bristol, Rhode Island has through a student engineering exercise, successfully modified a small FLUPSY to run completely on renewable (solar) energy.

This was achieved by taking an existing FLUPSY design based on a floating raft (app. 10' x 20') with a center discharge trough having 8 silos (2 ft cubes) attached around the perimeter of the center trough (4 to a side). The original design is conventionally powered by a 110VAC submersible "Ice Eater" axial flow pump, pumping water out of the center trough through a side-end discharge. The approximate flow rate is 900gpm and it can generate a 2" head differential between the outside and the inside of the discharge trough. The Solar alt- FLUPSY design uses the same basic configuration except the axial flow pump has been modified to allow for the motor to be above the deck level (i.e. not submerged) and the discharge position has been moved to the center of the trough.

The modifications to the system to allow renewable solar energy to power the FLUPSY include:

• Fabrication of a shaft-driven axial flow pump to allow the motor to be installed at deck level;
• Replacement the standard 110VAC motor with a 90VDC motor;
• Installation of solar panels, battery storage system and charge controller; and
• Modification of the raft to support the new components.

A prototype raft operated during the 2009 growing season by Roger Williams University.          During that season it was successfully used to bring seed of the clam Mercenaria mercenaria (analogous to the Native cockle) through nursery culture.

2.3 New VIU next generation shellfish raft design

The necessity of creating better culture raft designs to effectively modernize the shellfish farming industry has been a significant priority to the BC shellfish culture industry. Recently, it has become apparent that the vast majority of industry infrastructure is in need of redesign, upgrades and new investment.

In a previous CSR project, we responded to industry need to develop a new shellfish aquaculture raft design using current state-of-the-art materials and techniques. The resulting “open” design has created next generation high quality rafts for the BC shellfish farming industry. We believe these will improve industry economic profitability and environmental sustainability. Having long-life raft designs that will withstand significant loads from high wind and wave action will reduce industry’s contribution of debris on beaches and subsequently save farmers time and money to replace lost and broken equipment.

The Centre for Shellfish Research conducted an open-source development process with industry, component manufacturers and experts. Expert engineers (Dynamic Systems Analysis) were engaged to work with the project team to assist in developing prototype designs and to provide design recommendations to independent industry efforts. Virtual dynamic systems modelling was employed to simulate how various materials and structures would perform in a dynamic marine environment and greatly accelerated the range of materials and concepts that could be analyzed prior to physical prototyping.

Existing industry standard trimaran and catamaran rafts were modelled to determine weaknesses and safety factors and used as a guideline in new designs. A wide variety of materials were simulated to determine which would be most suitable as potential component materials in terms of both minimum strengths and cost effectiveness.

After testing more than 30 designs virtually, four final designs based on two styles were developed for physical prototyping. Final designs use a combination of primary structural beams (steel) and secondary interstitial beams. The supporting structure of the rafts is a combination of galvanized steel 4” steel 'T' and 'I' beams, assembled with galvanized bolts in order that rafts can be bolted together onsite with simple tools. Standard steel stock comes in 40’ lengths and to maximize the use of steel, the raft dimensions were extended to 27.6’ x 27.6’ (2/3d’s) of a standard beam. Rotomolded dock floats (billets) were selected.

The results of this project maybe found in our Final Report available online at www.viu.ca/csr.

3.0 Project Objectives

The objectives of this project component are expected to produce:

• A “farm scale” extensive nursery system that will allow the commercialization of native species such as the native cockle and other shellfish species;
• Greater sustainability for the shellfish industry via integration of renewable energy sources, reduced environmental risk and operational costs;
• Further integration and usefulness of the new CSR next generation shellfish culture raft design;
• A FLUPSY design that will have greater social acceptance through lower profile, consistency with shellfish culture rafts, add quiet operations; and
• Provision of FLUPSY design to industry for further adaption and improvement.

The following design criteria were established to guide design criteria during FLUPSY development:

• Adapt Roger Williams University FLUPSY design for Vancouver Island solar irradiance;
• Adapt FLUPSY components to be a “bolt-on” option for VIU next generation shellfish raft;
• Use “off-the-shelf” components wherever possible to facilitate future adaptation;
• Develop the design to be as “low profile” as possible and to be able to be integrated in normal shellfish raft farm profiles; and
• Create a modular design that can be expandable.

4.0 Operations and Initial Observations.

Initial testing indicates that the raft is achieving all desired performance and outcomes. However, we will not be able to document a full analysis until the completion of at least one growing season. Ultimate success will depend on:

• the ability of the system to provide biological (pumping) requirements;
• the ability to harvest, store and minimize the use of renewable energy; and
• the ability to survive in the marine environment under regular operating and maintenance conditions.

We hope that additional industry input and comment while the unit is operating at our research farm in Deep Bay will assist us in suggesting further improvements. We have so far made the following observations:

• The use of 36volts for the system design significantly reduces the potential components that can be added to the system. We would like to investigate the engineering ramifications of modifying the system to work via 110AC (inverter) or more common 12 Volt.
• With the FLUPSY anchored out on the raft grid, the energy generation system could easily be increased through the addition of a consumer wind turbine system. This is complicated however by the requirement to charge at 36 Volts in the existing configuration.
• Production models of the FLUPSY could benefit from the replacement of our fabricated wood solar panel racking with more commercial aluminium racking products. This could potentially add more flexibility in adjusting for annual changes in sun inclination and direction. This however could be expected to drive construction costs up.
• We used suspended ballast to trim the FLUPSY. We note that ACE Roto-mold provider of the raft floats also makes flotation chambers similar to those used on the CSR raft which may be filled with water or air. These might be a more efficient way of providing and adjusting trim.
• Which is better? A vertical axial pump or a paddlewheel? To date we have been able to find no quantifiable information in this regard. In this application we must consider the question in terms of both pumping volume and energy consumption. Hopefully in situ testing at a later date will allow us to answer this question.