id	keyword
american_scientific_journal-9186	energy
american_scientific_journal-9186	heat
american_scientific_journal-9186	greenhouses
american_scientific_journal-9186	solar
american_scientific_journal-9186	pump
american_scientific_journal-9186	electricity
american_scientific_journal-9186	carbon
american_scientific_journal-9186	system
american_scientific_journal-9186	heating
american_scientific_journal-9186	heat pump