Welcome Back!

The ENVS student groups have been primarily focused this week on drawing up chapter drafts for our class’s final report. This report includes group progress summaries, guiding documents, and recommendations for the future of the project to be passed along to the Greenhouse Committee following the conclusion of the class. The report will be accompanied by a final presentation summarizing major findings and recommendations. The presentation will take place virtually and will be open to Dartmouth Environmental Studies faculty, the Greenhouse Committee, and project interviewees including Dartmouth faculty, Town of Hanover Officials, and area farmers. However, we do have a few project updates from this week to share with you! 

Team Updates:

The Design Team drew up two alternative preliminary design plans for the Big Green Energy House. One plan is catered to building on the foundation of the existing O-Farm greenhouse and focuses on renovation requirements. The other plan is suited to the two other locations identified for a larger greenhouse structure. More details on the alternative greenhouse placement options are in the previous post. Both plans include approximate calculations for the size of the GAHT system to be installed in the Big Green Energy House. 

 

Next week, the Design Team will focus on determining the soil type and temperature gradient beneath the existing  O-Farm greenhouse structure to gauge its hospitality for crops. They are also working toward securing an assessment of the existing greenhouse foundation from a College-approved structural engineer and creating an approximate project cost estimate. 

 

The Infrastructure Team met with Dartmouth Director of Sustainability Rosi Kerr. She recommends building the Big Green Energy House on top of the existing O-Farm greenhouse foundation because of the slow permitting process and zoning inaccessibility of the alternative placement options. She also provided valuable information on auxiliary funding sources for future greenhouse upkeep, garnering alumni and Dartmouth Development Office support for the project, and the institutional hurdles to realizing Dartmouth infrastructure projects. 

 

The Infrastructure Team also met for a second time with Dartmouth Organic Farm Programs and Operations Manager and member of the Greenhouse Committee Laura Braasch to discuss long-term goals for the Organic Farm, creative renovations on the exiting O-Farm greenhouse foundation, O-Farm labor limitations, greenhouse construction cost, and O-Farm desires for a new greenhouse structure. 

 

The Farmer Relations Team executed a meeting between the ENVS50 class, members of the Greenhouse Committee, and Michelle Shane, greenhouse manager at  Cedar Circle Farm & Education Center. Students had the opportunity to ask questions to Michelle directly about building, funding, maintaining, and advertising an educational greenhouse. The team also spoke over the phone with a representative from Red Shirt Farm and set up a time to speak with a representative from Hip Peas Farm. 

 

The Barn Raising Team compiled a minute-by-minute plan, a fact-sheet, and a COVID-19 protocol for a future educational event on GAHT systems during the upcoming Summer, Fall, or Spring terms. They’ve also begun reaching out to Dartmouth community members and local NGOs to recruit volunteers and educators for the event. 

 

The Synthesis Team returned structural edits on all teams’ final report chapter drafts and sent out an invitation to Upper Valley and Dartmouth community members to attend the class’s final presentation. We also coordinated with Environmental Studies Department Administrator Kim Wind to send out project information, the blog link, and our social media handles through the Environmental Studies listserv and the Dartmouth VOX newsletter. We’re currently creating the final presentation outline and planning a class for this coming Tuesday to help get all of the students on the same page as we collaborate on our final ENVS50 deliverables. 

 

Thanks for checking in, and see you here next week! 

At this stage in the project, the Greenhouse Committee and ENVS50 class are considering options for auxiliary sources of funding on top of the funding that we have already applied for to construct the Dartmouth Big Green Energy House. With this goal comes some major switchups in plans for the Dartmouth Big Green-Energy House, so we have lots to report from the ENVS50 groups. 

 

In consideration of the long term trajectory and original master plan for the Dartmouth Organic Farm, the Design Team is exploring the possibility of constructing an entirely new greenhouse structure. Originally, the team had been planning to demolish the current O-Farm greenhouse and build a 20 X 60 foot passive solar greenhouse on top of the existing foundation. The red building in Figure 1 represents this plan. 

Figure 1: Potential Big Green-Energy House Sites

 

However, the team is now considering building a new 30 X 100 foot structure. The Design Team identified two potential locations for a larger passive solar greenhouse. One option is to construct it on the site of the current O-Farm hoophouse, represented by the orange building on Figure 1. If the team takes this route, the greenhouse will have to be rotated towards the road to provide adequate southern light exposure. The other option is to build it on the plot of land represented by the yellow building on Figure 1. 

 

The Design Team is currently making calculations to determine the size and number of GAHT systems required to control climate in a larger greenhouse. They’re also working with the Infrastructure Team to identify zoning restrictions on the two new potential sites and to generate construction cost estimates. 

 

The Infrastructure Team reiterated that conservation easements on the O-Farm land and the required 50-foot setback line from Lyme Road constitute the largest obstacles to siting a greenhouse structure. Figure 2 illustrates buildable land at the O-Farm. 

Figure 2: Buildable land at the O-Farm considering conservation easement and zoning restrictions 

 

Combined, Figure 1 and Figure 2 highlight a major obstacle to constructing a 30 X 100 foot Big Green-Energy House that the teams must navigate. If the new greenhouse were to be built on top of the 20 X 60 foot foundation of the existing greenhouse (the red building in Figure 1), the new structure would count as a renovation on the old structure, and it would be grandfathered into the zoning exception that allows the current O-Farm greenhouse to peek over the 50-foot setback line from Lyme Road. 

 

If an entirely new 30 X 100 foot greenhouse were to be built on the site of the existing O-Farm hoophouse (the orange building in Figure 1) and rotated to increase essential southern light exposure, this structure would also peek over the 50-foot setback line. However, because this greenhouse would be an entirely new structure, the 50-foot setback line zoning exception would not be applicable. An entirely new greenhouse built on the site represented by the yellow building in Figure 1 encounters the same problem. 

 

The team believes it may be possible to negotiate zoning restrictions and conservation easements with the Town of Hanover, and we’ll keep you updated on any progress on building permit developments. 

 

The Infrastructure Team also met with Tim McNamara, Associate Director of Facilities Operations & Management, once again. Tim informed the team that any project exceeding $10,000 must receive at least three bids from Dartmouth-approved contractors. These bids, or an estimate by a professional evaluator, will help inform the potential cost of construction for the Big Green-Energy House. A finalized design plan is required to receive this estimate. Additionally, Dartmouth’s project manager would assume control of a project of this magnitude, reducing the Greenhouse Committee’s control of the project. 

 

Finally, the Infrastructure Team is investigating ways to fund upkeep of the Big Green Energy House through Dartmouth. 

 

The Barn-Raising Team and the Synthesis Team are reaching out to Dartmouth student groups and local nonprofit agricultural organizations to determine their interest in attending, participating in, and volunteering to be educators and leaders at an informational event on GAHT systems. The Barn-Raising Team is considering whether to make outdoor event plans for the Summer Term, when less students will be on campus, or the Fall Term, when the weather in Hanover is more variable. They’re currently writing a script and fact sheet for the event as well as planning educational activities and refreshments. 

 

The Farmer Relations Team set up a virtual meeting with Michelle Shane, the Greenhouse Manager at Cedar Circle Farm & Education Center, and ENVS50 scheduled for next week. The meeting will give student groups a chance to ask questions directly to a farming professional about passive solar greenhouse construction and management, sustainable farm education, and community farmer needs. The Farmer Relations Team also continues to navigate scheduling conflicts during peak growing season to speak with other area farmers. 

 

The Synthesis Team is continuing to post on social media and working with Dartmouth’s Sustainability Office and Environmental Studies Department to get the word out about the Big Green-Energy House project. We’re designing the final presentation for the conclusion of the ENVS50 class and extending invitations to virtually attend the presentation to ENVS faculty, the Greenhouse Committee, the Town of Hanover, area farmers, and others who have helped to make the initial stages of the Big Green Energy House planning possible. Finally, we’re assisting other student groups as they continue to communicate with one another and community stakeholders. Next week, we will begin editing and synthesising chapter drafts for ENVS50’s final report. 

 

Thanks for tuning in and check back next week for more project updates! 

  The GAHT System Temperature Control Process

The Dartmouth Big Green-Energy House will use a Ground to Air Heat Transfer (GAHT) system, otherwise known as a climate battery, to control the climate of our passive solar greenhouse. As the blog’s initial post indicates, the GAHT system uses a fan to send hot air into a below-ground pipe system where this heat is absorbed by soil. ENVS50’s course textbook, The Year-Round Solar Greenhouse, also tells us that warm and humid air from the greenhouse condenses within the pipe system. This phase change causes energy, and therefore heat, to transfer from air into the condensed droplets of water, further cooling the air to travel from the pipes back into the greenhouse (192).

 

The heat stored in the soil and below-ground pipe system is rereleased into the greenhouse through conduction when the temperature cools above ground. GAHT systems can be customized depending on greenhouse climate control requirements. Among other variables the team must consider in designing an effective GAHT system for the Dartmouth Big-Green Energy House are pipe length and size, pipe layering and orientation, and fan power (208).

 

Group Updates

 

This week in ENVS50, we made progress navigating construction regulations, generating a design model for the Big Green-Energy House, and connecting with the Dartmouth and Upper Valley communities. 

 

The Farmer Relations team continues to reach out to area farmers to gauge their expertise and desires for sustainable greenhouse infrastructure. They’ve also checked back in with other student groups to supplement their list of outreach questions and have invited other students in the class to sit in on their Zoom calls and make personal connections with local farmers. 

 

The Infrastructure Team researched backup funding opportunities for the Big Green-Energy House. Alternative funding sources include the Northeast Sustainable Agriculture Research and Education (SARE) Program, the New Hampshire Department of Agriculture, the Whole Foods Local Producer Loan Program, the Organic Farming Research Foundation, and the USDA Conservation Stewardship Program. 

 

The Infrastructure Team and the Design Team met with Tim McNamara, Associate Director of Campus Planning and Facilities at Dartmouth, to talk about feasible design models and ADA compliance in the Big Green-Energy House. The teams learned in this meeting that the current Dartmouth Organic Farm greenhouse is grandfathered into the front yard zoning setback line, so completely demolishing the existing greenhouse structure and building the passive solar greenhouse on the current footprint isn’t an option. However, any new structure built on the existing foundation counts as a renovation and is subject to the same zoning exceptions as the current greenhouse structure. 

 

The Design Team then met with Chris Polashenski, an adjunct professor at the Thayer School of Engineering at Dartmouth. Professor Polashenski built and designed the current O-Farm greenhouse as an engineering student at Dartmouth in 2007. He provided the Design Team with the original design documents for the current O-Farm greenhouse as well a list of the building materials and foundation measurements. 

 

The Barn Raising Team received positive feedback from student groups at Dartmouth including the Farm Club about student interest in participating in the construction of the Big Green-Energy House. They’re forging ahead with plans for a future event where students and community members can learn about implementing GAHT systems in passive solar greenhouses.

 

The Synthesis Team continues to post updates on the Dartmouth Big Green-Energy House project to our social media platforms. We asked the Dartmouth Sustainability (username: sustainabledartmouth) and Dartmouth O-Farm (username: the.o.farm) accounts on Instagram to share our social media platforms and have gained a larger audience. The team is currently trying to post an announcement about our project in Dartmouth’s VOX Daily newsletter. 

 

All of the student teams also drafted outlines for their chapters in the ENVS50 final report, which will be delivered to our community partners upon the conclusion of the class to inform them of our research, progress, and recommendations for future steps. The Synthesis Team will spend the weekend looking through these outlines in search of information gaps and redundancies across groups.

 

As always, thanks for checking in on the project, and visit this page again next week for more project updates and information! 

 

Citation:

Schiller, L. & Plinke, M. (2016). The Year-Round Solar Greenhouse: How to Design and Build a Net-Zero Energy Greenhouse. New Society Publishers.

ENVS50 has been hard at work this week drawing up an initial greenhouse design, identifying recyclable elements of the current Dartmouth Organic Farm greenhouse, navigating College and the Town of Hanover construction regulations, creating lasting relationships with local farmers interested in sustainable agriculture, and creating educational resources and events for community members. Throughout the Spring term, we’re drawing inspiration for the Big Green-Energy House design and implementation from our course textbook, The Year Round Solar Greenhouse (please reference the citation at the end of this post). Below are a few of our important takeaways thus far! 

• Why Go Solar?

 

Greenhouses increase local food production, but this doesn’t always mean lower fossil fuel emissions. Shipping produce from areas of the country with hospitable crop weather can actually be less fossil-fuel intensive than growing them in greenhouse environments with intensive artificial light and heat demands (9). By applying strategic solar design, solar greenhouses work in tandem with the natural environment to create optimal growing conditions without fossil fuel inputs (22). 

• Solar Greenhouse Design Considerations

 

Light Exposure: 

 

Ideally, the Big Green-Energy House will be rectangular with a long southward facing wall and shorter eastern and western walls to maximize sun exposure (40). The structure may be oriented up to forty-five degrees southeast without significant loss of light (40). 

 

Glazing and steep wall and roof angles maximize heat and light in the winter (6) and dislodge snow buildup (65), all essential considerations in the extended winter months of Hanover, New Hampshire. This design structure, in addition to strategic shading, also reduces summer heat and light to reduce overheating in the greenhouse during warmer months (6). However, the Dartmouth Big-Green Energy House must conform to area building codes to determine the possible height of the structure (65). According to the Infrastructure Team, Hanover adheres to international building codes with more stringent regulations than the local building codes applied in other parts of New Hampshire. This poses an added restriction to our greenhouse design. 

 

Insulation:

 

Glazed areas of the northern, eastern, and western walls and roof of the greenhouse, which receive less sunlight than the southern exposure, should be insulated to reduce heat loss (6). Heat loss can be further reduced by insulating cracks and seams in the greenhouse structure (86). We should also insulate the greenhouse around the perimeter of the ground plane (78). This not only reduces heat loss through cracks and seams where the structure meets the earth, but also connects the interior greenhouse to soil temperature that is less volatile than air temperature (79). 

 

Temperature Control: 

 

Heat can be stored during the warmer daytime hours and released during the night through various thermal storage systems (6). We will be using a Ground to Air Heat Transfer (GAHT) system, detailed in the first blog post, to regulate our greenhouse temperature. Ventilation systems, such as exhaust fans or passive vents, also control greenhouse temperature by releasing excess heat from the interior. Exhaust fans are more precise than passive solar vents. They often run on fossil fuels but can be solar-powered. Solar exhaust fans only regulate greenhouse temperature during periods when the sun is shining and the greenhouse is most likely to overheat (100). Alternatively, passive ventilation cannot be as precisely controlled as exhaust fans, but they respond to the temperature of surrounding air and require no electricity (95). 

 

Student Group Updates

 

This week, ENVS50 has encountered some obstacles and taken some strides in the Big Green Energy House project. Here are a few brief updates:

 

The Design Team took measurements of the current O-Farm greenhouse in order to generate a new design option with similar dimensions. They’re trying to find the original greenhouse blueprint to determine the depth of the foundation and whether or not we’ll have to dig it out to build the new passive solar greenhouse structure. 

 

The Infrastructure Team spoke with Bernard Haskell, Assistant Director of Residential Operations at Dartmouth, to glean information on College construction protocols and material acquisition. They are currently trying to establish a liaison with the Dartmouth Office of Planning, Design & Construction and navigate the international building codes that apply to Hanover. 

 

The Farmer Relations Team is continuing to establish virtual communications with area farmers due to the COVID-19 pandemic. They’ve gathered questions from the other groups and are challenged to find amenable times to speak with farmers during the current growing season. 

 

The Barn Raising Team is planning an educational event on GAHT systems that will be open to project stakeholders and the community. They are trying to construct plans that can be easily executed by other project stakeholders after the conclusion of the ENVS50 class. 

 

The Synthesis Team is communicating information between student groups, publicizing the project’s social media, and brainstorming successful ways to notify the Upper Valley community about the Dartmouth Big Green-Energy House beyond our social media campaign. 

 

Citation: 

Schiller, L., & Plinke, M. (2016). The Year-Round Solar Greenhouse: How to Design and Build a Net-Zero Energy Greenhouse. New Society Publishers.

This week, ENVS50 has worked to solidify the Big Green-Energy House vision, gain insight from the local farming community, and coordinate with our project partners. 

Progress This Week

The Farmer Relations Team spoke with Dave Chapman at Longwind Farm, a certified organic tomato farm in Lyme, Vermont. According to Longwind’s website, Dave Chapman founded the farm in 1984 and continues to run it with state-of-the-art greenhouse technology that allows him and his team to start growing in early spring and continue producing into winter. The team is looking forward to communicating with him and his network of local farmers in the coming weeks! There could also be opportunities for collaboration between the farmer relations and design groups, as many of Dave’s observations revolved around proper greenhouse construction techniques.

The Infrastructure Team and representatives from the Green Design Team met with project partner and Dartmouth Organic Farm manager Laura Braasch to discuss zoning and conservation easement limitations on new infrastructure at the O-Farm. Only three acres of the O-Farm are currently zoned for building, including the sites with the barn, daycare center, and pizza oven are already located. The location of the project is further limited by Dartmouth College’s conservation easements. Conservation easements are voluntary legal agreements that protect conservation values by permanently limiting land use options. Dartmouth’s land conservation easements are intended to protect unique ecosystems, the historic Connecticut River floodplain, riverbank oak tree habitat, pastureland, and preserve walking trails and the land’s agrarian history. Laura advised the student partners that the most accessible place to locate the new passive solar greenhouse will be on the footprint of the old greenhouse, which is already in desperate need of renovation. 

The Green Design Team also gathered information on the research activity and O-Farm needs and visions to inform the Dartmouth Big Green-Energy House preliminarily blueprint. The project team will need to balance the labor capacity of the O-Farm employees and volunteers with research and growing goals. If researchers and farm managers collaborate on upkeep, the Green Design Team has tentatively determined that a passive solar greenhouse approximately the same size as the greenhouse currently located at the O-Farm would allow project partners enough space to conduct research on the efficacy of passive solar greenhouse technology. It’s important to highlight that the O-Farm is financially supported by Dartmouth College regardless of its profitability. This means that we can dedicate a significant portion of the Dartmouth Big Green-Energy House to researching the efficacy of our passive solar greenhouse design rather than crop production. 

The Barn Raising Team met with an O-Farm Sustainability Fellow to discuss the vision, timeline, and obstacles to holding an in-person event. The biggest constraints to an in-person barn-raising event would be covid restrictions and transportation. The team brainstormed ideas such as building parts of the greenhouse in pieces around campus (like the green) then bringing those pieces together in one greenhouse-raising event. In the coming week they are working on developing an educational component for participants that would attend the event, as well as collaborating with the Farmer relations group and Design team to learn about the interests of local farmers and feasibility of a building event. 

The Synthesis Team conducted research on effective intergroup communication and brainstormed ways to reach a wide range of stakeholders. We created introduction posts on Instagram (follow us @DartmouthBigGreenEnergyHouse) and Facebook (follow the Dartmouth Big Green Energy House page). We’re beginning the foundations of a newsletter to distribute to the Dartmouth community after the completion of ENVS50, and we’re working together with the Farmer Relations team to determine which outreach materials are most accessible to local farmers. 

Future Goals

The Farmer Relations Team will engage in planning this upcoming week to establish some rules and procedures for engaging with local farmers. They are also gathering questions from other student subteams which will help to direct the initial Big Green-Energy House blueprint.  

The Infrastructure Team will review zoning documents provided by the town of Hanover to determine limitations on building on the site of the current greenhouse and possible areas for expansion. The team also plans to meet with Dartmouth Sustainability Director Rosi Kerr to talk about specific pathways to infrastructure development at Dartmouth. 

The Green Design Team will investigate zoning specifics to concretize the anticipated size of the passive solar greenhouse. They have submitted questions to the Farmer Relations Team to acquire farmer input on greenhouse construction. 

The Barn Raising Team and the Green Design Team will communicate about the necessary materials for a future barn raising event.

The Synthesis Team will continue to post updates on the blog and social media as well as coordinate communication among the various student groups. We will also begin research on the most accessible ways to distribute knowledge to a range of stakeholders which extends beyond the Dartmouth sustainability community. 

Thank you for tuning in and check back next Friday for more updates on the project! 

Introduction to the Dartmouth Big-Green Energy House project

Greenhouses are essential infrastructure for four-season farmers in the Northeast. Unfortunately, they frequently rely on fossil fuel inputs to satisfy the intensive heating and lighting required to maintain a controlled growing environment. Dartmouth faculty and staff, the Dartmouth Environmental Studies Department capstone course (ENVS 50), and the Dartmouth Organic Farm are teaming up to create the ‘Dartmouth Big-Green Energy House,’ an innovative passive solar greenhouse with minimal fossil fuel inputs. The Dartmouth Big-Green Energy House is intended to serve as a lighthouse model for area farmers hoping to reduce fossil fuel emissions in their agricultural systems. 

What is a passive solar greenhouse?

Traditional greenhouses rely on fossil fuels to control the internal environment. A passive solar greenhouse optimizes solar radiation, geothermal energy, and strategic infrastructure instead. At this point in the project, the Dartmouth Big-Green Energy House team plans to implement a ground-to-air heat transfer (GAHT) system, also known as a climate battery, in the final greenhouse design. In the daytime, a fan draws excess heat and humidity from the greenhouse atmosphere into a below-ground pipe system. This heat and humidity is then stored in the soil until the greenhouse temperature drops at night. When the greenhouse becomes cool, the fan propels the cold greenhouse air into the underground pipes. This air is heated by the thermal energy stored in the soil during the day and then re-released into the greenhouse. 

However, greenhouses equipped with climate batteries still suffer from significant heat loss, and research on the impact of GAHT systems on carbon sequestration and crop productivity is limited. The Dartmouth Big-Green Energy team will incorporate crop research components into its project to determine the environmental impact of GAHT systems and the feasibility of adopting climate batteries as low-emission alternatives to traditional greenhouse systems. The team will also combine the GAHT system with energy efficient structural design to minimize heat loss. These design components may include glazing materials, insulation materials, strategic structural design and building positioning. 

The Team

Assistant Professor Theresa Ong of the Environmental Studies Department is our agroecology expert. Her work focuses on the ways that ecosystems and food production are influenced by interactions between the environment, organisms, and people.

Assistant Professor Caitlin Hicks Pries of the Biological Sciences Department is our biology expert. Her work investigates terrestrial carbon cycles and carbon within ecosystems.

Laura Braasch is the O-Farm Program Manager. Molly McBride is a Sustainability Fellow With the O-Farm. Together, they are our O-Farm leaders and project visionaries.

Alana Danieu is the project research assistant.

The Spring ‘21 ENVS 50 Class are student partners in the project. Throughout the spring term, they will help to design, publicize, and plan the greenhouse. The students are split up into teams focusing on infrastructure, farmer outreach, green design, barn raising, and synthesis/outreach. This blog will provide updates on each team’s work in the next nine weeks. 

First Progress report

We’re in the beginning stages of planning, but we’ve made some great progress so far! Our Dartmouth faculty and staff partners have submitted a grant application to the Arthur L. Irving Institute for Energy and Society, and we hope to hear back from them in the coming weeks. In the meantime, here’s what the students have been up to:

The Infrastructure Team is researching alternative funding for the project and beginning research on building restrictions at the O-Farm. 

The Farmer Outreach Team is speaking to area farmers about the challenges of greenhouse growing, their aspirations for fossil fuel input reduction, and their feedback on our preliminary passive solar design plan. They are also researching potential sources of funding for farmers who are interested in replicating the Dartmouth Big Green Energy House post-construction. They were even able to visit Long Wind Farms in Lyme, NH to meet with manager Dave Chapman about the project! 

The Green Design team is researching passive solar and geothermal energy and constructing a game-plan for the Dartmouth Big Green-Energy House design. 

The Barn Raising Team is beginning to plan an event to publicize the Dartmouth Big Green-Energy House to community members and local farmers. 

The Synthesis/Outreach group is facilitating intergroup communication and setting up social media platforms to get Dartmouth students, local farmers, and community members excited about the project. 

We will be posting a project update each Friday, so please stay tuned! 

 

 

Be sure to follow us on our social media accounts for more updates!

 

Instagram: @DartmouthBigGreenEnergyHouse

Facebook Page: Dartmouth Big Green Energy House