Solar Turbine Prototype at Factor e Farm

2008-08-21T13:52:26Z

Stulutions: /* Part Sourcing Information */

(Linked from [[Solar_Turbine]])
=Email Group=

Join the [http://groups.google.com/group/solar-turbine Solar Turbine email group]

=Introduction=

We are building a replicable solar thermal concentrator electric power system - on the kW scale. The closest system that we found to our design is:

[[Image:ISE_slats.jpg]]

[http://www.solarpaces.org/Tasks/Task4/task_iv.htm Source]. We should identify and contact the designers.

=System Overview=

Here is a general overview of what I could see happening in the approximate August 15 - September 1 period.

I think we can be happy if we construct and fine tune the simple 16-slat solar collector design. This would include the foundation, collector, receiver, followed by some data acquisition. I think that when we obtain steam production data, we could use those results to motivate some form of collaboration towards sourcing a steam engine.

=Design Drawings=

The site will be prepared by leveling with a tractor and blade. We are building on the conceptual drawings in [[Solar Concentrators]] and [[Solar_Concentrator_Technical_Drawings]]:

#[[Solar Concentrator Foundation]] - CEB posts are presently our first choice, but we may revert to lumber if technical difficulties arise
#[[Concentrator Structure]] - collector tube mounting, slat mounting, connecting posts together
#[[Mirror Slats]] - rotation support bearing, bearing mounts, rod, slats, mechanical fasteners
#[[Tracking]] - sensor, actuator, gearing
#[[Solar Concentrator Tube]] - glazing, insulation and cover, tubing connection, attachment to support structure, alignment mechanism

=Reflectors, Collector, and Data Acquisition=

[[Image:turbine_prototype.jpg]]

Overview. Steam is our preferred choice due to its simplicity. I am not sure whether steam will yield the highest efficiency, but we can optimize this point by going to higher temperatures. Advantage: a sustainable resource. Disadvantage: freezes in winter

=Updated Designs=

Here is an updated proposition from Ben, end of July, 2008:

[[Image:ganged1.jpg]]

[[Image:ganged2.jpg]]

[[Image:ganged3.jpg]]

Marcin proposes the following implementation:

[[Image:ganged_frame.jpg]]

Note the above design has been refined 8.8.08 to $750 prototype cost, drawings forthcoming - Marcin

==Foundation==

A concept drawing is here:

http://openfarmtech.org/index.php?title=Solar_Concentrator_Technical_Drawings

By August 15, we should have the [[LifeTrac]] tractor, [[CEB Press]], and footer auger ready for action. We are planning on building a CEB block foundation, 1x1 foot wide. The process for this involves augering a 2 foot diameter hole 3 feet deep, laying cement-stabilized CEB blocks as a post foundation, and laying gravel around these posts. The posts will stick up about 2 feet above the ground to make a comfortable working surface above the ground, but not so tall that the overall structure begins to suffer from wind loads. The 2 constraints for how low we can go to the ground are (1), splashing from the ground during rain, (2) comfortable height for array building and maintenance.

I foresee using 2x4 or 4x4 treated lumber as bond beams on top of the CEB block pillars.

''Advantages'': Low cost foundation, with the only material costs being gravel. CEB blocks are produced on-site from local soils.

''Disadvantages'': More labor intensive than treated lumber post-and-beam foundations, though not more labor intensive than the whole lifecycle of post-and-beam, if labor to produce and transport said lumber is considered.

==Reflectors==

At present, the least expensive, lasting option is glass, but we may consider aluminized mylar for a temporary solution - [http://www.specialty-lights.com/730025.html $55 for 400 sq ft]. Mylar does not last long, but it would suffice to do the testing. Glass breaks easily in hailstorms - so we would want to consider a single or double layer of chicken wire across the whole array.

===Tensioned Reflective Film Reflector Design===

[[Image:wingedreflector.jpg]]

===How to Cut Glass===

http://chestofbooks.com/home-improvement/woodworking/Handicraft-For-Boys/How-to-Cut-Glass.html

YouTube - http://www.youtube.com/watch?v=y2wt9S7SApo&feature=related

==Mirror Slat Mounting==

(now outdated)

Details of tracking and glazing mounting are proposed:

This is a detail of each of the foundation pillars that support the reflector array. The entire array foundation is 3 by 11 pillars.

[[Image:reflector_detail.jpg]]

==Collector==

Collector consists of 6 tubes made of galvanized, 1" steel pipe. It should have selective reflection coating - $70/gallon from http://solec.com, and be insulated from the back. We should design the collector for testing collector performance with and without and standard glass cover.

===Feedwater System===

Passive drippin of water into the collector tubes during testing will yield data on steam generation at atmospheric pressure. If we want to generate steam at pressure, we need a pumped or valved feedwater system. Here is a valved system concept detail:

[[Image:valve_detail.jpg]]

==Data Acquisition==

Steam generation rate should be measured by condensing the steam into a container filled with a known volume of water.

Temperature and pressure measurements should be taken at both ends of the collector tube. Temperature of the steam should be taken by includin a tee in the steam outlet line. Temperature should also be measured in the liquid reservoir.

=People=

Work will occur at Factor e Farm.

Stewart - visiting from August 18 - September 3.

Elliot - visiting from August 13 to August 23.

Chris and Mel - visiting August 1 for 2-3 days or for what's needed

=Part Sourcing Information=

Here are some prices that I found out. Please submit others:
*mirrored plexi glass - $4/sq.ft - [http://www.eplastics.com/Plastic/Plexiglass_Acrylic_Sheet_Mirrored]
*Reflectech film - $2-3/sq ft in sub-acre coverage quantities - [http://www.reflectechsolar.com/pricing.html]
*Mirror
**'''$291 plus shipping''' - for 360 pieces of 12x10" tile - [http://www.dollaritem.com/Dollar_Store/shoppingcart.asp?xItem=1&SessionID={78DC8371-C6F6-4A98-9EA2-AE5764880BC6}]
**Menards has mirror tile at $1.5/sq ft
*Aluminized Mylar -
**'''HydroponicsUSA'''
***'''$40''' - for thin 1 mil 400 sq ft - [http://www.hydroponicsusa.com/servlet/the-86024/%3EMylar-&-Poly-Reflectors/Detail]
***$20 for 100 sq ft 2 mil - [http://www.hydroponicsusa.com/servlet/the-79306/Mylar-2-mil-48%22/Detail]
***$13 for 100 sq ft 1 mil - [http://www.hydroponicsusa.com/servlet/the-78982/Mylar-1-mil-48%22/Detail]
***$65 for 400 sq ft 2 mil - [http://www.hydroponicsusa.com/servlet/the-80064/Mylar-2-mil-48%22/Detail]
**$30 for 100 sq ft - [http://www.plantlightinghydroponics.com/mylar-mil-50-reflective-film-p-321.html]
**$15 for 40 sq ft 2 mil - [http://www.mirrorsheeting.com/]

**$44 for 400 sq ft 1 mil - [http://www.mirrorsheeting.com/]
*Mirror holders - steel studs, which can be opened up to the 6" width of the mirrors to be held - are structurally sound and relatively inexpensive
**Menards has 3 5/8"x1 1/2" steel studs, 10 foot long, for $4.50
**Others?
*Selective solar coating - $70/gallon from [http://www.solec.org/solkotehome.htm#PRODUCT%20SPECIFICATIONS Solec]
*Foundation
**CEB block & 6 tons of gravel - gravel for '''$150'''
**4x4s may be utilized with Ben's updated design - [http://openfarmtech.org/weblog/?p=279]
*Collector tube:
**16 10 foot sections of 1" galvanized pipe - $16 each, '''$256'''
**8 more of the above for collector tube supports - '''$128'''
*Insulation - [http://www.infraredheaters.com/insulati.htm] - $110
*Other:
**Bearings for reflector slats - $30 for 100 at [http://www.vxb.com/page/bearings/PROD/100Skate vxb.com], need 160 for total of '''$60'''
**10' of 1/2" Electric Mechanical Tube, galvanized steel - $2.89 at Menards, need 16, total of '''$48'''
**3/8" rod, 6', $10 at McMaster Carr, [http://www.mcmaster.com/ Part # 9120K64], need 26, total of '''$260'''
**107 sq ft of gauge 18 steel sheet, $2/sq ft at 7.11.08 prices - '''$214'''

=Background Calculations, Tables, Data=

It is extremely useful - in order to gain an appreciation of the power available from solar energy - to go through the basic calculations of power yields from our system, and to compare those yields to the energy obtainable from sustainably-harvested biomass energy. See these notes [http://openfarmtech.org/index.php?title=Comparison_of_Biomass_and_Solar_Energy_Yields here].

Pipe dimensions - [http://www.engineeringtoolbox.com/ansi-steel-pipes-d_305.html]

=Implementation=

We are documenting the building process and our practical learnings from Factor e Farm [http://openfarmtech.org/index.php?title=Solar_Turbine_Implementation here].

Open Source Ecology - User contributions [en]

Solar Turbine Prototype at Factor e Farm