Renewable Home Power, Backup, Heat and Air Conditioning

Princeton Satellite Systems has been in a leader in renewable energy with its SunStation home solar power system with battery backup. We introduced this product back in 2013. SunStation has lithium-ion phosphate batteries, the most stable and reliable batteries for home use. The core of the system is the Outback Inverter that seamlessly switches from grid power to internal power.

The solar system in the installation produces 7.3 kW of power, much more than the house needed for electric power including charging a Nissan Leaf and Toyota Prius Prime. The heating and air conditioning system was nearing its end-of-life so we decided to replace it with a geothermal heat pump. A heat pump is essentially an air conditioner that can both reject heat to a source and absorb heat from a source. The problem with both is that when the outside temperature is high, for rejecting heat, and low, for absorbing heat, the system loses efficiency. Modern air-source heat pumps are very efficient but do need backup resistance heating in some climates.

A ground source heat pump, or geothermal heat pump, uses the ground as the medium for absorbing or rejecting heat. The option we chose, due to land constraints, is to have two wells several hundred feet deep as the source. Alternatives are trenching, or a pond if you have one in your yard. The ground is always at around 50 deg F. The system was sized so that it rarely, if ever, needs resistance heating.

The geothermal system, which is made by WaterFurnace, was installed by Princeton Air. No changes to the SunStation were needed. The core geothermal system is shown below. The valves to the ground loops are in the foreground and the geothermal system is on the left.

The lines that run to the outside ground loops are shown below.

The system has a preheater for the (still gas) hot water heater. The gas water heater was less than a year old, so it didn’t make sense to replace it. The preheater is an electric hot water heater that does not have the heating coils connected.

The SunStation is shown below. The Outback inverter is on the bottom left. The boxes on top provide arc protection, which is now included in the inverter. The batteries on on the right and the battery management electronics between the inverter and the battery cabinet.

The well digging was quite a project. This picture shows the drilling rig.

This second picture shows the yard after the drilling was complete. Drilling took three days total.

The following system shows the SunStation with geothermal in operation. The Prius Prime is charging which is most of the load. The system is still sending considerable power to the grid. On average the house powers itself and two other houses.

Geothermal, with solar and battery backup is the ideal solution for new homes and for renovations to existing homes. There is no reason to even have a gas hookup anymore. Contact us at SunStation for more information

Interstellar Documentary and New Novel for Fusion Fans

So fusion fans, there are two new ways to see DFD explored as fusion propulsion in the popular media:

  1. The Living Universe documentary series now on Curiosity Stream
  2. The Enceladus Mission” novel now in English from Amazon

The Living Universe is both a feature film for IMAX theaters and now a four-part documentary series. We blogged about our interviews in January and the series is now available on Curiosity Stream, a service dedicated to documentaries! Episode 2,”The Explorers” features a segment on DFD narrated by PSS engineer Stephanie Thomas, in addition to discussing plasma and antimatter propulsion. Here is an article about the series from Broadway World. You need to sign up for an account on Curiosity Stream to watch, which is free for 7 days and then $3 per month.

“The Encedalus Mission” by internationally best-selling hard science fiction author Brandon Q. Morris was originally written in German, and features the DFD as the propulsion technology on a mission to study newly detected life in the Saturn system; an array of six DFDs power the spaceship.  Early reviews are favorable! The book is available in paperback or for Kindle.

Send us a comment and tell us what you think if you watch the show or read the book!

Phase II NASA STTR on superconducting magnets selected!

We are pleased to announce that our Phase II STTR proposal, “Superconducting Coils for Small Nuclear Fusion Rocket Engines,” was one of 20 selected for award by NASA in this year’s round! The full list of winners is posted on NASA’s website.

Our briefing chart prepared as part of the proposal is shown below:Briefing chart

We will be building a testbed with a split-pair superconducting coil (two windings with a gap between them) and performing experiments to assess the impact of operating the magnets in the vicinity of the FRC plasma. Applications of the technology go beyond fusion reactors, for example science payloads and high-performance motors for hybrid electric aircraft.

PFRC Paper Accepted to Physics of Plasmas

Our colleague Eugene Evans of PPPL has had his paper, “Particle-in-cell studies of fast-ion slowing-down rates in cool tenuous magnetized plasma,” accepted for publication in Physics of Plasmas. The article is tentatively scheduled for the April 2018 issue. A quote from the reviewer:

The paper … is an interesting, well-written paper that uses PIC to build upon earlier direct numerical simulation methods based on molecular dynamics. The authors present a clearly written discussion of the scaling properties of slowing down theory to support their numerical studies. The authors do a very good job describing the simulation approach they take… Of particular note in the paper is the good agreement between their numerical data and the sub-thermal model even when the effective computational log(lambda) was on the order of 1…  the authors did not stop with their results but instead applied their conclusions to the FRC reactor, predicting that the neutron production rate is 100 times lower than a conventional DT Tokamak.

This paper is key to the low radiation levels claimed for our PFRC design, and hence the Direct Fusion Drive. The fast ion slowing-down is what causes the tritium and other fusion ash to exit the machine. You can view a preprint on arXiv.

We will post again once the paper is published and available from Physics of Plasmas.

Fusion Power Associates Meeting

I attended the 2017 Fusion Power Associates meeting in Washington, D.C. on December 6 and 7. Fusion Power Associates is a non-profit, tax-exempt research and educational foundation, providing timely information on the status of fusion development and other applications of plasma science and fusion research.

The annual meeting brought together experts in all areas of nuclear fusion research including scientists and engineers from ITER, the Princeton Plasma Physics LaboratoryTAE TechnologiesGeneral Atomic and many others! The meeting gave a great overview of the state of nuclear fusion power generation. We learned that ITER is 50% complete and on its way to first plasma in 2025. Planning has begun on Demo, the follow-on to ITER.

The Joint European Torus plans a D-T campaign in 2019 and hopes to set new fusion benchmarks. We learned about Korea Superconducting Tokamak Advanced Research  (KStar). It has achieved longer than 70 second pulses in H-mode and has suppressed ELM for more than 34 seconds. KStar has in-vessel control coils.

There were several speakers from the University of Rochester along with colleagues from the national laboratories talking about advances in laser compression of fuel pellets. This work is for nuclear weapons research but could be applied to inertial confinement fusion.

I gave the last talk of the meeting on Princeton Satellite Systems and PPPL’s work on DFD, nuclear fusion propulsion for spacecraft.

Second DFD Patent Awarded

We are pleased to report that an additional patent has been awarded for DFD! US Patent 9,822,769, “Method and Apparatus to Produce High Specific Impulse and Moderate Thrust from a Fusion-Powered Rocket Engine”, was published on Nov. 21, 2017. It’s now available from the US patent office website!

Here is a link to the patent from the Department of Energy’s Energy Innovation Portal! The inventor on the patent are Dr. Cohen, of PPPL, and three PSS engineers: Gary Pajer, Michael Paluszek, and Yosef Razin.

Fusion Rocket Engine

The first patent, “Method to Reduce Neutron Production in Small Clean Fusion Reactors,” was issued on September 9, 2017. The patent is available on Patentscope.

Rendezvous with 1I/’Oumuamua

An interstellar asteroid, 1I/’Oumuamua, was discovered on a highly hyperbolic orbit by Robert Weryk on October 19, 2017 moving with a speed of  26.32 km/s. It appears to come from the direction of the star Vega in the constellation Lyra. It would be really great to send a mission to rendezvous and fly in formation with 1I/’Oumuamua to study the asteroid. The high velocity makes it hard to do with current technology.

Direct Fusion Drive (DFD) might provide a answer. We designed a spacecraft with a 1 MW DFD power plant and assumed a launch on March 16, 2030. The following plots show the trajectory and the force, mass and power of the spacecraft during the 23 year mission. As you can see we don’t have to use the full 1 MW for propulsion so we have plenty of power for data transmission and the science payload.

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The code for this analysis will be available in Release 2018.1 of the Princeton Satellite Systems  Spacecraft Control Toolbox for MATLAB.